What is the origin of the term Prima Scriptura and the background against which it was defined?

The term Trinity is not in the Bible but the doctrine is clearly supported by the New Testament. Similarly, the wikipedia article shows how the concept of "the primacy of scripture" has been in use implicitly (although implemented differently) by different Christian groups throughout history. Before Reformation the concept was used in contrast with the concept of Tradition, and after Reformation it was used in contrast with both Sola Scriptura and Tradition

What is the origin of the term?

In both Trinity and Prima Scriptura, I argue that: usage came first, then the term came later, then different groups use the term differently to name what needs to be communicated. But putting on my amateur etymologist hat and armed with Google Books search I was able to find a 1997 paper Sola Scriptura, Inerrantist Fundamentalism, and the Wesleyan Quadrilateral: Is "No Creed But the Bible" A Workable Solution? by Woodrow W. Whidden from Andrews University. In his paper in which he used the term "Prima Scriptura" he credited Albert Outler in the footnote as follows:

¹⁴As to the background for my use of the term prima scriptura, I am consciously indebted to the introductory comments of Albert Outler in his classic introductory anthology of Wesley's writings, John Wesley (New York: Oxford Univ. Press, 1964), 28.

The book "John Wesley" edited by Albert C. Outler is in Google Books and the following is the relevant quote from page 28 (part of the chapter "Introduction"):

The great Protestant watchwords of sola fide and sola Scriptura were also fundamentals in Wesley's doctrine of authority. But early and late, he interpreted solus to mean "primarily" rather than "solely" or "exclusively."¹⁰¹ Faith is the primary reality in Christian experience but not its totality. It is, Wesley urged, a means -- a necessary means -- to a still higher end: "Faith ... is only the handmaid of love. ..."¹⁰² The goal of the Christian life is holiness, "the fullness of faith." This means the consecration of the whole self to God and to the neighbor in love. This, in turn, involves a process of corporate discipline and effort, guided by the motives of "devotion," by which he meant the delivering up of one's whole life to God. The outcome to be expected in this endeavor is the renewal of the imago Dei, mutilated by sin and ruined by waywardness. But our aspiration to holiness is as truly a function of faith as justification itself is. The faith that justifies bears its fruits in the faith that works by love.

And in fact it was Albert C. Outler also who coined the term "Wesleyan Quadrilateral" according to wikipedia referencing the same book.

Since Albert Outler himself didn't use the term Prima Scriptura it looks like the term was coined by Woodrow W. Whidden in his 1997 paper, borrowing the concept from Albert Outler's book John Wesley published in 1964. This is the earliest reference I can find on Google.

I also found a 2017 Master's thesis The Hermeneutical Frameworks of Fernando Canale and Fritz Guy: Sola and Prima Scriptura and the Science-Theology Relationship in which not only Woodrow Whidden's paper was cited, but he was in the advising committee. Looks like a typical case of a professor transmitting his key ideas to his "academic descendants".

Thesis abstract:

This thesis presents research on the hermeneutical frameworks of sola and prima Scriptura and how they affect the science-theology relationship. It specifically focuses on the writings of Fernando Canale and Fritz Guy who hold opposing views on both sola and prima Scriptura and the relationship between science and theology. Canale argues for a sola Scriptura framework with science governed by theology, whereas Guy argues for a prima Scriptura framework with science and theology working independently of each other.

This thesis begins with a brief historical overview of the issues and then moves into describing Canale’s and Guy’s views. It ends with an evaluation of their positions and some suggestions for a more comprehensive framework that can incorporate valuable aspects of each scholar’s proposals.

The research concludes that what is needed is a hermeneutical framework that combines sola and prima Scriptura principles (as indicated but not fully developed by Canale). Currently, Canale’s and Guy’s frameworks, viewed separately, do not take into account important aspects of the science-theology relationship. A combination sola-prima framework is helpful for clarifying the relations between science and theology and for guiding the influence of other sources/resources on theology.

The background against which it was defined

As rje's answer and my own answer for another question indicated, one way to solve the restriction of sola scriptura and to delineate the evolution of the usage is to identify 4 different ways that Scripture is used in conjunction with Tradition. This is what Dr. Keith Mathison did, building on Heiko Oberman's work as described in the wikipedia article on Dr. Mathison's book The Shape of Sola Scriptura, by identifying 4 different interactions named Tradition 0, Tradition I, Tradition II, and Tradition III. Therefore, in my view, Prima Scriptura as a term is simply another way to name what is conceptually similar to Tradition I.

But of course the devil is in the detail, and as philologists and exegetes struggle with this task on a daily basis, the meaning of the term has a life of its own, to be potentially chronicled and defined and published as a journal article if the community so desires. In addition to the above 2 papers about Prima Scriptura there is a 2011 book titled Prima Scriptura: An Introduction to New Testament Interpretation which is also available through Scribd by N. Clayton Croy author and tutor at the University of Oxford.

The book itself did not offer a history of the term, but simply uses it as a book title and as a concept to differentiate against sola scriptura in the author's own usage. The book is a textbook of exegetical method that of course includes heavy discussion of the shade of sola scriptura it is advocating. Published in 2011, it naturally includes Dr. Mathison's book in its bibliography as you can see in the quote below as "Mathison, 2001". The book also references Whidden's paper above as "Whidden, 1997" and uses it to support reason #2 in the second quote below, but doesn't credit Whidden for the term prima scriptura, maybe by 2011 the book author thought it was already common currency.

There are only 2 places within the book where he mentions prima scriptura, (I did text search in Scribd):

Quote when he summarizes chapter 3 "Evaluating and Contemporizing the Text" under A Preview of the Method in This Book:

3. Evaluating and contemporizing the text (hermeneutics). The third stage is distinguished from exegesis not so much by differentiating “what the text meant” from “what the text means” (cf. Stendahl, 1962: 419–20), but rather by taking the textual meaning and simply asking, What does the contemporary Christian community do with this? How do we receive the meaning of the text? Can we receive it? What is its significance for us in the twenty-first century? Needless to say, this hermeneutical stage is one of the most crucial in the interpretive process. Sharp disagreements between Christians nowadays, especially on divisive matters of ethics and public policy, often hinge on how one adjudicates the results of the exegetical phase. At this point, other criteria are brought in, what one might call “hermeneutical adjuncts.” For although the Bible is an authoritative source for the faith and practice of Christians, its authority does not operate in a vacuum. If it did do so, we could adopt the Reformation motto sola scriptura in the most absolute sense and largely do away with this third step. But in fact, nearly all Christian traditions employ one or more additional criteria such as tradition, reason, and experience. A more realistic motto, then, would be prima scriptura: Scripture as the primary authority, but in conjunction with and mediated by other authorities. Both revelation and reason are gifts from God; indeed, they are interrelated gifts, since one cannot grasp a written, historical revelation without the use of reason. From this stage a contemporary interpretation of the text emerges.

Quote toward beginning of chapter 3, within pages 130-34:

Sola Scriptura or Prima Scriptura?

The title of this book, Prima Scriptura, is a fairly transparent play on the Reformation slogan sola scriptura (Scripture alone). The slogan implies that the Reformers made a sharp distinction between Scripture and tradition and then drew solely upon the former. But several historians and theologians point out that in practice sola scriptura did not exclude other sources. David Steinmetz clarifies: “While it is true that the reformers were at first optimistic that it would be possible to teach and preach a theology that was wholly biblical, they rarely intended to exclude theological sources that were non-biblical. Sola scriptura generally meant prima scriptura, Scripture as the final source and norm by which all theological sources and arguments were to be judged, not Scripture as the sole source of theological wisdom” (2002: 129; see also Whidden, 1997: 216–23; Mathison, 2001; Charles, 2002: 143n58; Olson, 2003: 53; and M. M. Thompson, 2008: 13). Sola scriptura was meant to exclude “only what is contrary to Scripture, not everything except what is explicitly written in Scripture” (Hinlicky, 1999: 395).

So the thoroughgoing, exclusivist notion of sola scriptura was not actually what the mainstream Reformers practiced. Luther and Calvin frequently appealed to the church fathers and the creeds, for example, as authentic expressions of the apostolic faith (McGrath, 1999: 153). It is true that some of the more radical proponents of the Reformation rejected tradition outright, but their movement quickly degenerated into ideological chaos precisely because their theology, lacking the moorings that tradition could provide, spun off in a multitude of directions. Alister McGrath distinguishes these “radical Reformers” from the “magisterial Reformers,” noting that the latter “had a very positive understanding of tradition” (McGrath, 1999: 154). They were “painfully aware of the threat of individualism, and attempted to avoid this threat by stressing the church’s traditional interpretation of Scripture where this traditional interpretation was regarded as correct” (McGrath, 1999: 155). Tradition was rejected only when it contradicted or went far beyond Scripture.

An exclusive appeal to Scripture was untenable for a number of reasons. First, tradition (in the sense of the theology and practices of the church in the first few centuries) was directly involved in the creation and delimitation of Scripture. [... skipped ...]

Second, Scripture does not function in a vacuum (Hays, 1996: 209). As we saw in chapter 1, everyone reads from a certain location, through certain lenses, and in the light of a particular tradition and life experiences. Though objectivity is always the goal, we cannot transport ourselves back to the first century and read the New Testament as if the intervening millennia had not occurred. We are steeped in tradition, whether consciously or unconsciously. This is true even for those who say they have “no creed but the Bible.” All Christians, whether they belong to the Catholic tradition going back two millennia or to a denomination of much more recent vintage, have “historic and contemporary figures who have exercised powerful, formative influences over their interpretation of Scripture” (Whidden, 1997: 213). These mentors are part of the reason for the theological pluralism that exists in Christianity. Indeed, even “among groups that strenuously profess fidelity to the Bible as their sole authority,” there is a “bewildering array of doctrinal options” (Whidden, 1997: 214). An exclusivist notion of sola scriptura does not produce theological uniformity precisely because the influence of tradition is everywhere at work. The point is forcefully made by Whidden: “No Bible-believer is strictly sola Scriptura in any arena of theological discourse—and this includes the most stridently fundamentalistic persons in the most conservative traditions of independent, Bible-oriented American churches” (1997: 220). Tradition shapes us all.

Finally, the scholarly dimension of the Christian tradition is what makes it possible for us to read the Scriptures today. [... skipped ...]

It therefore is incoherent to reject the role of ecclesiastical tradition in the interpretation of Scripture (Hinlicky, 1999: 395). One could even argue that the long-term effect of an exclusivist version of sola scriptura was harmful because it removed biblical interpretation from its natural context: the church. The final result of divorcing Scripture from its ecclesial context was “the complete secularization of Scripture itself” (Hinlicky, 1999: 395). This is especially apparent in public universities in the United States, but its effects are also seen in some private and even church-related institutions. [... skipped ...]

Some scholars seem prepared to write the obituary of sola scriptura. It would be preferable, however, to rehabilitate and clarify the principle along the lines of prima scriptura. Even some who would retain the traditional language recognize the need to correct distorted versions of the concept. Lutheran theologian Carl Braaten, for example, argues for the continuing affirmation of sola scriptura, but “not as a battle-cry against the church and its tradition. Rather, ‘sola scriptura’ means that everything essential in the original apostolic preaching which founded the church is written down in Scripture, and that no later tradition can negate or supersede it” (1981: 194, with original emphasis). Later traditions sometimes reinforce the gospel and sometimes undermine the gospel. The criterion that the church must use to judge these traditions is Scripture.

If we adopt prima scriptura in lieu of sola scriptura, we should not think that Scripture has thereby been demoted or devalued. Scripture is still the primary authority for Christian faith and life. If ever there is a conflict between Scripture and tradition, Scripture must have priority (Charles, 2002: 143). As one theologian put it, “In matters of theological development and debate, tradition should get a vote but never a veto” (Olson, 2003: 54). The classical statement of this quality of Scripture is norma normans non normata (apparently all classical statements must be in Latin): Scripture is “the norm or standard that regulates [all else, but is itself] not regulated [by any].” Scripture is what constitutes Christian identity and shapes Christian faith and practice. It has pride of place in Christian moral and theological deliberation.

It is an encouraging sign that Christians of different stripes are beginning to recognize the need for both Scripture and tradition, while usually understanding the latter as serving the former. [... skipped...]

So the role of Scripture and its relationship to tradition are better captured by the phrase prima scriptura than sola scriptura. Scripture is the primary authority, but its authority does not operate alone. I also remind the reader of a point made earlier: Scripture’s authority is derived rather than inherent. It is derived from God, who alone is the supreme authority over life and creation. “As important as canonical Scripture is in the Church, it is not its ultimate authority. That capacity belongs to the Word, the person of Jesus Christ, who is more than a text” (Work, 2002: 258). So Scripture derives its authority from God, and among the means commonly employed by Christians to discern the will and ways of God, Scripture is primary. But the word “primary” implies other means of discernment with a secondary or supportive role. So what are they?

Quadrilaterals, Trapezoids, and Triangles

[... this is the part where the book discussed AT LENGTH the Wesleyan Quadrilateral... ]