How many letters does the top answer for “consisting of only one type” have?

The most common answer is monotypic (9 letters).

Crossword clue: consisting of only one type

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

monotypic 9 letters wn-def

consisting of only one type

consisting of one sphere only. 60% similar → monospherical

consisting of only one morpheme 60% similar → monomorphemic

a composition consisting of one verse only. 50% similar → monostich