Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
2. aeterno, āre, v. a. [aeternus], to perpetuate, to immortalize (rare, perh. extant only in the two foll. exs.): litteris ac laudibus aeternare, Varr. ap. Non. 75, 20: virtutes in aevum, * Hor. C. 4, 14, 5.