Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† phallus, i, m., = φαλλός, a figure of an obscene shape, carried about at the festival of Bacchus, originally a symbol of the generative power of nature; a phallus, Arn. 5, 176; cf. Aug. Civ. Dei, 7, 21.