How many letters does the top answer for “in a square form or manner.” have?

The most common answer is squarely (8 letters).

Crossword clue: in a square form or manner.

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

squarely 8 letters web-def

directly and without evasion; not roundabout

in the form or manner of a specter. 50% similar → spectrally

in the form or manner of an amphitheater. 50% similar → amphitheatrically