Does "stream enterer" simply mean "devout Buddhist"?

Buddha gave about 50+ definitions (that i know of) of a stream enterer. And also what are not!

Pali cannons are very fragmented so this book is for free downloading..with citation to the english translator..

http://watnapahpong.com/static_media/Sotapanna_Handbook_English_version_30.pdf

One thing clear, Buddha allowed only him and one self to make a determination if you have been into "the stream". above book is very comprehensive. enjoy.

The following explains the first two distinct stages on the path to nirvana.

Stream-enterer: The first direct insight into selflessness is often the most powerful because it's unlike anything you've ever experienced before. For a timeless moment (which may last just an instant), no one is there — that is, there's no trace of a separate self anywhere. A feeling of tremendous relief, often accompanied by joy and bliss, generally follows the experience: At last, you've had the insight you've been seeking for so long. At last, you've "entered the stream" of realization.

When you become a stream-enterer, you can never again believe that you're really a separate self that lives inside your head and looks through your eyes. Your experience forever eliminates this illusion. When you look within, you can't find a self anywhere. In everyday life, however, you may still feel like a separate somebody and may still get caught up by greed, anger, ignorance, and various other negative feelings and patterns. Fortunately, the stage of stream-enterer also brings an unshakable confidence and dedication to the Buddhist spiritual path, so you're motivated to keep deepening and refining your realization.

Once-returner: After you become a stream-enterer, your practice includes reminding yourself of your new realization of "no-self," as well as paying attention to the ways that you're still attached and your resistance to life as it unfolds. After a period of time in which your concentration gets even stronger and your mind becomes even more tranquil, you have another direct insight into no-self. (Remember, knowing this truth as a concept or memory is one thing, but experiencing it directly, beyond the conceptual mind, is something else entirely.)

This insight (essentially the same as the first but even stronger and clearer) brings a significant reduction in attachment and aversion and the suffering that accompanies these states of mind. For example, occasional irritation and preference replace hatred and greed, which no longer have any hold over the once-returner. Someone who reaches this stage has only one more rebirth before becoming completely enlightened — hence the name once-returner.

I hope this will provide you sufficient information to understand what you were looking for. And remember these stages are achievable for the modern man. One way I know how is through regular practice of meditation. Simply put I would say it is the recolonization that your mind (ego mind) and you are two different things, by your self.

"Eckhart Tolle" is some one who talks about this situation

No, they're not describing the same kind of thing. Stream Entry (i.e. the thing which a Stream Enterer achieves) is a particular achievement en route to full enlightenment. Devoutness, then, is merely one aspect of living that may help one reach that achievement.

Another analogy is weight lifting. Someone can be "devout" in the sense of being serious. committed to going to the gym, faithful to the pursuit of increasing weight capability, and so on. And then "stream entry" is something like "can clean and jerk their own body-weight".

In other words, stream entry is a specific, well-described set of "objective" criteria in terms of attainment. Devout, on the other hand, could represent a way of approaching practice so as to achieve stream entry (i.e. to become a stream enterer).

Going back to your Catholic analogy, consider St Thomas Aquinas. He was, by all accounts, a devout Catholic. However, towards the end of his life he is recorded as having had some kind of spiritual experience which led him to say that all his prior work (the Summae etc) was "like straw". I suspect that he may have been referring to something like a Stream Entry experience, but it came along towards the end of (although maybe because of) a devout Catholic life.

No, a stream enterer is much more than that. A stream enterer has experienced Nibbana first hand and is changed in a permanent way because of it. Stream entry totally destroyes the first three fetters of self view, doubt about the validity of the teachings, and clinging to rites and rituals.

A person who knows the teachings of the Buddha are true and sincerely follows them to seek enlightenment but hasn't yet attained stream entry would be called a kaliyana putthujana, or good worldling.

(Added later)

Some other terms that might be what you are looking for are the terms Faith-follower and Dhamma-follower, which refer to individuals who have come to have come to an acceptance of the Dhamma either primarily through the quality of faith or of wisdom, but have not yet been able to directly perceive the truth of the Dhamma for themselves. For example, the Vinnana Sutta says:

At Savatthi. "Monks, eye-consciousness is inconstant, changeable, alterable. Ear-consciousness... Nose-consciousness... Tongue-consciousness... Body-consciousness... Intellect-consciousness is inconstant, changeable, alterable.

"One who has conviction & belief that these phenomena are this way is called a faith-follower: one who has entered the orderliness of rightness, entered the plane of people of integrity, transcended the plane of the run-of-the-mill. He is incapable of doing any deed by which he might be reborn in hell, in the animal womb, or in the realm of hungry shades. He is incapable of passing away until he has realized the fruit of stream-entry.

"One who, after pondering with a modicum of discernment, has accepted that these phenomena are this way is called a Dhamma-follower: one who has entered the orderliness of rightness, entered the plane of people of integrity, transcended the plane of the run-of-the-mill. He is incapable of doing any deed by which he might be reborn in hell, in the animal womb, or in the realm of hungry shades. He is incapable of passing away until he has realized the fruit of stream-entry.

"One who knows and sees that these phenomena are this way is called a stream-enterer, steadfast, never again destined for states of woe, headed for self-awakening." http://www.accesstoinsight.org/tipitaka/sn/sn25/sn25.003.than.html