I ran across this:

http://www.christian-thinktank.com/fabprof2.html

and, as I'm not particularly well versed in these matters, I was wondering how truthful it is.

More precisely, are the definitions it gives of almah and bethulah correct?

All the examples they give for claiming betula can mean non-virgin show nothing of the sort:

Ezek 23:3: the two women were virgins and lost their virginities in Egypt. "The breasts of their virginity" means "their breasts while they were virgins".

Joel 1:8: Hebrew ba'al means "husband"; whether the husband has committed intercourse is not stated. Specifically, ba'al n'ureha (the husband of her youth) means "the one who was wedded/betrothed to her in youth".

Esther 2:17: the Persian king simply took a virgin every night and devirginized her. It was a common oriental palace custom, as also told in the Arabian Nights.

"Esther 2:17: the Persian king simply took a virgin every night and devirginized her. It was a common oriental palace custom, as also told in the Arabian Nights."

Our pal Gilgamesh gets credit for starting the custom of going on the honeymoon with the bride & groom and getting first dibs on the bride!

Thanks for your help, guys. Better to check that it is nonsense before I confidently claim so, though, isn't it?!