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Ordinary words can be converted into technical terms.
For e.g. in English, the ordinary word "reduction" means "the action or fact of making something smaller or less in amount, degree, or size".
But in medicine, a technical term was created out of "reduction" which means "the restoration of a displaced or broken part of the body to its proper position or alignment by manipulation or other surgical procedure."
So, similarly, piti may have an ordinary meaning in Pali and other Indian languages, but for jhana, the Buddha turned it into a technical term.
You can find some info in the Rapture (piti) section of "The Jhanas in Theravada Buddhist Meditation" by Ven. Henepola Gunaratana:
Rapture (piti)
The third factor present in the first jhana is piti, usually translated as joy or rapture. In the suttas piti is sometimes said to arise from another quality called pamojja, translated as joy or gladness, which springs up with the abandonment of the five hindrances. When the disciple sees the five hindrances abandoned in himself "gladness arises within him; thus gladdened, rapture arises in him; and when he is rapturous his body becomes tranquil" (D.i,73). Tranquillity in turn leads to happiness, on the basis of which the mind becomes concentrated. Thus rapture precedes the actual arising of the first jhana, but persists through the remaining stages up to the third jhana.
The Vibhanga defines piti as "gladness, joy, joyfulness, mirth, merriment, exultation, exhilaration, and satisfaction of mind" (Vbh. 257). The commentaries ascribe to it the characteristic of endearing, the function of refreshing the body and mind or pervading with rapture, and the manifestation as elation (Vism.143; PP.149). Shwe Zan Aung explains that "piti abstracted means interest of varying degrees of intensity, in an object felt as desirable or as calculated to bring happiness."
When defined in terms of agency, piti is that which creates interest in the object; when defined in terms of its nature it is the interest in the object. Because it creates a positive interest in the object, the jhana factor of rapture is able to counter and suppress the hindrance of ill will, a state of aversion implying a negative evaluation of the object.
Rapture is graded into five categories: minor rapture, momentary rapture, showering rapture, uplifting rapture and pervading rapture. Minor rapture is generally the first to appear in the progressive development of meditation; it is capable of causing the hairs of the body to rise. Momentary rapture, which is like lightning, comes next but cannot be sustained for long. Showering rapture runs through the body in waves, producing a thrill but without leaving a lasting impact. Uplifting rapture, which can cause levitation, is more sustained but still tends to disturb concentration, The form of rapture most conductive to the attainment of jhana is all-pervading rapture, which is said to suffuse the whole body so that it becomes like a full bladder or like a mountain cavern inundated with a mighty flood of water. The Visuddhimagga states that what is intended by the jhana factor of rapture is this all-pervading rapture "which is the root of absorption and comes by growth into association with absorption" (Vism.144; PP.151)