How many letters does the top answer for “a day's work; also, a fixed amount of work, whether more or less than that of a day.” have?

The most common answer is darg (4 letters).

Crossword clue: a day's work; also, a fixed amount of work, whether more or less than that of a day.

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

darg 4 letters web-def

A day's work; also, a fixed amount of work, whether more or less than that of a day. [Local, Eng. & Scott]

dargue 6 letters web-def

A day's work; also, a fixed amount of work, whether more or less than that of a day. [Local, Eng. & Scott]