Where did the term “tower shield” come from?

Solution 1:

It originates in Homer Iliad 7.219:

Αἴας δ᾽ ἐγγύθεν ἦλθε φέρων σάκος ἠΰτε πύργον:
And Ajax came close, carrying a shield like a tower:

In typically Homeric fashion, the line recurs verbatim a couple of times, at 11.485 & 17.128. Translation is mine for the nonce. The link is to the Perseus Project. Both English translations available there, Butler 1898 and Murray 1924, render πύργον as “wall” (as does Lattimore 1951), though the entries for πύργος in the LSJ and Autenrieth (Homeric) lexica begin by glossing it “tower.” Pope in 1715 rendered it “tower-like shield” for the latter two loci, and Chapman a century earlier went with “like a tower, his shield” and “a target like a tower.”