How many letters does the top answer for “of the cup-shaped socket that receives the head of the thigh bone” have?

The most common answer is acetabular (10 letters).

Crossword clue: of the cup-shaped socket that receives the head of the thigh bone

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

acetabular 10 letters wn-def

of the cup-shaped socket that receives the head of the thigh bone

cotyloid 8 letters wn-def

of the cup-shaped socket that receives the head of the thigh bone