also: いっせい
noun
Refers to a single vocal utterance: a call, a shout, or a brief vocal sound. Often used in expressions like 一声かける (to call out to someone) or 一声で (with a single word).
彼は一声かけてから部屋に入った。
He called out before entering the room.
一声で返事をした。
I answered with a single word.
声 is the general word for 'voice' or 'sound made by a person or animal'. 一声 emphasizes a single utterance or call.
Compound of 一 (one) and 声 (voice). The reading ひとこえ is the native Japanese reading (kun'yomi), while いっせい is the Sino-Japanese reading (on'yomi).