How many letters does the top answer for “a description of the signs of disease.” have?

The most common answer is semeiography (12 letters).

Crossword clue: a description of the signs of disease.

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

semeiography 12 letters web-def

A description of the signs of disease.

semiography 11 letters web-def

A description of the signs of disease.

a description or classification of diseases. 50% similar → nosography