How many letters does the top answer for “of or pertaining to coins; relating to the science of coins or medals.” have?

The most common answer is numismatic (10 letters).

Crossword clue: of or pertaining to coins; relating to the science of coins or medals.

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

numismatic 10 letters web-def

Of or pertaining to coins; relating to the science of coins or medals.

numismatical 12 letters web-def

Of or pertaining to coins; relating to the science of coins or medals.

the science of coins and medals. 60% similar → numismatics