Entry 1 sense Webster, 1913 Coterminous /(k?-t?r"m?-n?s)/ · Co·ter·mi·nous · IPA /kəˈtɝ.mɪ.nəs/ 01 a. Bordering; conterminous; -- followed by with. 1. Bordering; conterminous; -- followed by with.