Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
palmētum, i, n. [1. palma], a palmgrove, Hor. Ep. 2, 2, 184: Hiericus palmetis consita, Plin. 5, 14, 15, § 70; cf. Tac. H. 5, 6.
In sing., Just. 36, 3, 4.