One's childhood; the time when someone was a child. Used to talk about memories or states from that period.
子供の頃、よく近所の川で遊んだ。
When I was a child I often played in the nearby river.
子供の頃の友達と再会した。
I met up again with a friend from my childhood.
子供の頃はピアノを習っていました。
I took piano lessons when I was a child.
彼女は子供の頃から動物が好きだった。
She liked animals since childhood.