PAL

Ptolemaeus Arabus et Latinus

_ (the underscore) is the placeholder for exactly one character.
% (the percent sign) is the placeholder for no, one or more than one character.
%% (two percent signs) is the placeholder for no, one or more than one character, but not for blank space (so that a search ends at word boundaries).

At the beginning and at the end, these placeholders are superfluous.

particular ‘characteristic’

English

References: Alm. Toomer: 76
Translation of:
Greek: ἰδίωμα [Alm. Heiberg: II.1, 89:12; II.6, 101:7,10]
Synonyms:
(special) characteristic[Alm. Toomer: 82]