How many letters does the top answer for “a small shallow cup or drinking vessel.” have?

The most common answer is quaich (6 letters).

Crossword clue: a small shallow cup or drinking vessel.

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

quaich 6 letters web-def

A small shallow cup or drinking vessel. [Scot.] [Written also quegh.]

quaigh 6 letters web-def

A small shallow cup or drinking vessel. [Scot.] [Written also quegh.]

a small can or drinking vessel. 50% similar → cannikin