The headword, a collective feminine noun in the nominative (and vocative) singular, literally means a cutting all round, and thus a mutilation. But in Polybius the sense is more usually the outline, general form or the effects, appointments of a person or thing; see generally LSJ s.v. and pi 1187. The entry is presumably generated by the instances given, which are the accusative and genitive singular forms, respectively.
[1] Polybius 31.26.6 (web address 1). It describes the transfer of the substantial personal appointments of Aemilia Tertia (d. 163/2; cf. alphaiota 198, alpha 3167, and pi 1295), wife of Publius Cornelius Scipio Africanus (236-183; OCD(4) s.v.; pi 2054; Walbank, vol. II, pp. 191ff.), on her death, by her nephew (and grandson by adoption) Publius Cornelius Scipio Aemilianus Africanus (185/4-129; OCD(4) s.v.; alphaiota 199) to his mother Papiria, not Aemilia's mother as the present excerpt indicates; see Walbank, vol. III, pp. 503-5; Büttner-Wobst, p. 351; and Diodorus Siculus 31.27.3.
[2] Polybius fr. 198 (Büttner-Wobst). Büttner-Wobst (p. 540) notes that Schweighäuser doubted the attribution of this unplaced fragment to Polybius.