1To nod (one's head) to show assent, understanding, or agreement; to bow one's head in agreement.
話を聞いて、彼は静かに頷いた。
After listening, he quietly nodded.
説明に納得すると、参加者全員が頷いた。
When they were convinced by the explanation, all the participants nodded.
質問に対して教師は目で合図し、学生が頷く。
The teacher signaled with her eyes in response to the question, and the student nodded.
彼女は苦笑しながら小さく頷いた。
She smiled wryly and gave a small nod.