Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† tē̆trăo, ōnis, m., = τετράων, a heatkcock, moor-fowl, Plin. 10, 22, 29, § 56; Suet. Calig. 22 med.; Tert. adv. Marc. 1, 13 fin.