Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Lingŏnes, um, m., a people in Celtic Gaul, whence the modern name of their chief city, Langres, Caes. B. G. 1, 26; Plin. 4, 17, 31, § 106.
Afterwards dwelling on the Po, Liv. 5, 35, 2.
Hence,