> After seeing your separate comment that you sometimes confuse meet and join (as in John #4 above) because their standard English meanings are similar, I began confusing them too:-)
See what a great teacher I am? I can not only transmit my knowledge, I can also transmit my confusion!
> I think of meet as what is common to the two -- the point at which they meet -- so that's the intersection. Joining implies combining them to make something bigger, which is the union.
Yes, this feels like the original motivation of those terms. It should help me keep them straight.