For the unglossed headword (Pisum sativum) see LSJ s.v. pi/sos (commonly accented, as here, as piso/s). It is probably included here because of its appearances in Old Attic Comedy (Aristophanes, Eupolis); cf. under tau 295 (where however pisw=n may be incorrect).
This is one of the many Suda entries which juxtapose similar-looking words which have quite different meanings. (In this instance the body of the entry, i.e. the material from 'Also' onwards, is reported by Adler as a marginal addition to ms A. Ms V also lacks this part, and ms F omits the whole entry.)
[1] Better spelled with double sigma: Procopius, De aedificiis [On Buildings] 1.1.37 (web address 1); and see generally LSJ s.v. pesso/s, III, 'in Archit., cubic mass of building, terrace'. See pi 1384 with notes.