How do I solve 10 across in Press and Journal Cryptic unknown?

Question

Accepted Answer

10 across reads "Oh, was heard when offered French water" (3 letters); the answer is EAU. It's a homophone clue: the answer sounds like another word. Indicators like 'reportedly', 'we hear', or 'sounds like' point to a word that's pronounced similarly to the answer. The full step-by-step breakdown is on this page.

Oh, was heard when offered French water (3)

10A — Oh, was heard when offered French water (3) — EAU