How many letters does the top answer for “the head of a city government” have?

The most common answer is mayor (5 letters).

Crossword clue: the head of a city government

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

mayor 5 letters wn-def

the head of a city government

a meeting of heads of governments 50% similar → summit

head of government scientist 50% similar → nitithada

the head of a state government 50% similar → governor