Joel Hoffman posted yesterday that "the Greek phrase en gastri" means "in the womb." (He was looking at how Matthew used it with another Greek word "echousa" that Hoffman says means "holding." Hoffman is wanting to suggest that, for this phrase, Bible translators tend not to produce a "myopic translation" that would reproduce each Greek word -- i.e., myopic with "the English words 'in' and 'womb'" or myopic as "Holding in the womb." Matthew's phrase, Hoffman explains, "is Greek for 'pregnant,' or — as used to be common — 'with child'.")
But would anyone care to know that Homer, Hesiod, Sophocles, Euripides, Aristophanes, and Xenophon did not ever use the phrase with specific reference to a woman or a woman's conception of a baby? Rather, for these writers and storytellers, ἐν γαστρὶ referred to something in or around the "belly," "stomach," "paunch," and "[gluttonous] appetite."
And would anyone care to know that there was a metaphorical shift in how this word was used that seems to be traceable to Plato? Plato, who railed against the poets, the sophists, and playwrights and their use of language, was the first to use this Greek phrase (i.e., ἐν γαστρὶ) for a pregnant woman. In our extant texts of his, Plato only did this once, in his very last work, Laws, 792.e.3, where he puts the words in the mouth of the Athenian Stranger.
And would you be surprised that Aristotle, Plato's student, uses the phrase numerous times in his Generation of Animals and his History of Animals to refer (not metaphorically but rather scientifically) to the state of a female in conception or pregnancy? In fact, Aristotle rarely uses the phrase in any other way.
And Greek writers thereafter nearly exclusively use the phrase in reference to a conception in or the very womb of a woman.
update: As if you might care, here's a bit of Homer and then the bit of Matthew, both translated by Richmond Lattimore:
νειαίρῃ δ' ἐν γαστρὶ πάγη δολιχόσκιον ἔγχος,
and the far-shadowing spear was fixed in the lower belly,
Τοῦ δὲ Ἰησοῦ χριστοῦ ἡ γέννησις οὕτως ἦν.
Μνηστευθείσης τῆς μητρὸς αὐτοῦ Μαρίας τῷ Ἰωσήφ,
πρὶν ἢ συνελθεῖν αὐτούς,
εὑρέθη ἐν γαστρὶ ἔχουσα
ἐκ πνεύματος ἁγίου.
The birth of Jesus Christ came in this way:
Mary his mother was engaged to Joseph,
but before they came together
she was found to be with child,
by the Holy Spirit.