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

The most common answer is spectrally (10 letters).

Crossword clue: in the form or manner of a specter.

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

spectrally 10 letters web-def

of or relating to a spectrum

in a square form or manner. 50% similar → squarely

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