How many letters does the top answer for “a shield; especially one displaying a coat of arms” have?

The most common answer is escutcheon (10 letters).

Crossword clue: a shield; especially one displaying a coat of arms

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

escutcheon 10 letters wn-def

a shield; especially one displaying a coat of arms

scutcheon 9 letters wn-def

a shield; especially one displaying a coat of arms