Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
praesegmen, ĭnis, n. [praeseco], a piece cut off, a paring (ante- and postclass.): tonsor omnia abstulit praesegmina, Plaut. Aul. 2, 4, 33; cf.: praesegmina proprie Plautus in Aululariā ea dici voluit, quae unguibus eminulis praesecantur, Non. 151, 33: cadaverum, App. M. 2, p. 123, 24.