Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

alnus, i, f. [akin to Swed. al; A. S. aler; Germ. Eller; Engl. alder, elder], the alder, which flourishes in moist places: Betula alnus, Linn.; cf. Plin. 16, 40, 79, § 218; Cat. 17, 18; Verg. G. 2, 110: alnorum umbracula, Cic. Fragm. ap. Macr. S. 6, 4.
Poet., any thing made of alder-wood; so esp., a ship, since it was much used in ship-building: tunc alnos primum fluvii sensere cavatas, Verg. G. 1, 136; so id. ib. 2, 451; Luc. 2, 426: amica fretis, Stat. Th. 6, 106 al.; and of pales or posts, Luc. 2, 486; 4, 422.
The sisters of Phaëton, while bewailing his death, were changed to alders, acc. to Verg. E. 6, 62; cf. with it id. A. 10, 190; Claud. Fescenn. Nupt. Hon. 14.