aestŭārĭum, i, n. [aestus].
I A part of the sea-coast which , during the flood-tide , is overflowed , but at the ebb-tide is left covered with mud or slime , a marsh , ἀνάχυσις: aestuaria sunt omnia, quā mare vicissim tum accedit, tum recedit, Gloss. ap. Fest. p. 380 Müll.: pedestria esse itinera concisa aestuariis, Caes. B. G. 3, 9: adfunditur autem aestuarium e mari flexuoso meatu, Plin. 5, 1, 1, § 3; Plin. Ep. 9, 23.— Also,
II A channel extending inland from the sea , and only filled with water at floodtide , a creek , inlet , Varr. R. R. 3, 17: in aestuaria ac paludes, Caes. B. G. 2, 28 Herz.; Tac. A. 2, 8; cf. id. Agr. 22.—
III In mining t. t., an air-hole , air-shaft : secundum puteum dextra ac sinistra fodiunt aestuaria, Plin. 31, 3, 28, § 49; cf. Vitr. 8, 7; Pall. 9, 9.