How many letters does the top answer for “a barrier constructed to contain the flow of water or to keep out the sea” have?

The most common answer is dam (3 letters).

Crossword clue: a barrier constructed to contain the flow of water or to keep out the sea

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

dam 3 letters wn-def

a barrier constructed to contain the flow of water or to keep out the sea

dike 4 letters wn-def

a barrier constructed to contain the flow of water or to keep out the sea

dyke 4 letters wn-def

a barrier constructed to contain the flow of water or to keep out the sea