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.

circular ‘circular’

English

References: Alm. Toomer: 38. – PH Hamm: I.1:2, 44:7; I.1:5, 45:11
Translation of:
Greek: κυκλοτερής [Alm. Heiberg: I.3, 10:21]
Greek: ἐγκύκλιος [PH Heiberg: I.1:2, 70:7; I.1:5, 72:2]