How many letters does the top answer for “small opening (like a window in a door) through which business can be transacted” have?

The most common answer is grille (6 letters).

Crossword clue: small opening (like a window in a door) through which business can be transacted

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

grille 6 letters wn-def

small opening (like a window in a door) through which business can be transacted

wicket 6 letters wn-def

small opening (like a window in a door) through which business can be transacted