1.
back-channel response, verbal nod
Short verbal responses such as うん, ええ, そうですね given by a listener during conversation to show they are paying attention. A fundamental part of Japanese communication.
Key pattern
相槌を打つ is the standard collocation meaning "to give back-channel responses."
Etymology
From blacksmithing: 相 (mutual) + 槌 (hammer). Originally referred to the assistant smith striking the metal in rhythm with the master smith, hence the idea of responding in sync with the speaker.
Cultural note
Back-channeling is far more frequent and important in Japanese conversation than in English. Failure to give 相槌 can make the speaker feel ignored. Common responses include うん, ええ, そうですか, なるほど, and へえ.
Related Words
Related:
聞き役 (listener)