How many letters does the top answer for “one who holds up the train of a gown or robe on a ceremonial occasion” have?

The most common answer is trainbearer (11 letters).

Crossword clue: one who holds up the train of a gown or robe on a ceremonial occasion

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

trainbearer 11 letters wn-def

one who holds up the train of a gown or robe on a ceremonial occasion

one who holds up a train, as of a robe. 63% similar → trainbearer