Entry 1 sense Webster, 1913 Estuation · Es·tu·a·tion · IPA /ˌɛst͡ʃuˈeɪ̯.ʃən/ 01 n. The act of estuating; commotion, as of a fluid; agitation. 1. The act of estuating; commotion, as of a fluid; agitation. “The estuations of joys and fears.” — W. Montagu.