How many letters does the top answer for “the operation of introducing a catheter.” have?

The most common answer is catheterism (11 letters).

Crossword clue: the operation of introducing a catheter.

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

catheterism 11 letters web-def

The operation of introducing a catheter.

catheterization 15 letters web-def

the operation of introducing a catheter into the body

the operation of introducing a catheter into the body 75% similar → catheterisation, catheterization