Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
con-vinctĭo, ōnis, f. [vincio], gram. t. t., a connective particle, conjunction: veteres verba modo et nomina et convinctiones tradiderunt … in convinctionibus complexus eorum esse judicaverunt; quas conjunctiones a plerisque dici scio, sed haec videtur ex συνδέσμῳ magis propria translatio, Quint. 1, 4, 18.