peristasis
Could not find peristasim in Logeion dictionaries.
peristasim Noun: feminine accusative singular of peristasis
pĕristăsis, is, f., = περίστασις,
- a subject, theme, Petr. 48, 4.
peristasis, Akk. im, f. (περίστασις), der Gegenstand einer Rede, das Thema, declamatio, Petron. 48, 4.
pĕristăsis, (16) is, f. (περίστασις), sujet, argument : Petr. 48, 4.