Bow

 bow

 うなずく - this is the 'ok, ok, hai hai hai!' little head-bob.

 会釈する：えしゃく - ｔｏ　ｇｉｖｅ　ａ　ｈｅａｄ－ｎｏｄ in greeting - a sort of 'Sup?' head-nod. . .. N ｏｔ　ａ　ｆｕｌｌ　ｂｏｗ ; not the tiny, ’ OK 　ｉ　ｇｏｔ　ｉｔ’　ｋｉｎｄ　ｏｆ　ｎｏｄ either ．

 辞儀 - じぎ- serious 　formal bow