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.

مثل ... ومثل ثلثه ‘1 ⅓’

Arabic

References: Alm. MS Tunis:
Translation of:
Greek: ἐπίτριτος [Alm. Heiberg: I.10, 45:18-22]
Synonyms:
مثل وثلث[Alm. MS Leiden: f. 7v]