How many letters does the top answer for “utter a shrill cry” have?

The most common answer is pipe (4 letters).

Crossword clue: utter a shrill cry

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

pipe 4 letters wn-def

a tube with a small bowl at one end; used for smoking tobacco

shriek 6 letters wn-def

sharp piercing cry

a shrill cry or sound. 50% similar → skirl