頻回 is read as ひんかい (hinkai) and means frequent.
ひんかい
hinkai
ひんぱつ
frequent occurrence
ひんど
frequency (of occurrence)
ひんしゅつ
frequent appearance
ひんよう
frequent use
ひんどすう
frequency
ひんすう
ひんどぶんぷ
frequency distribution
ひんどいぞんせんたく
frequency-dependent selection
てっかい
withdrawal
じゅんかい
going around
せんかい
turning (an aircraft or ship)
だっかい
recovery