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.

عالم ‘universe’

Arabic. – Grammar: n.

References: Alm. MS Tunis: . – PH Morelon: I.4:1, 21:1
Translation of:
Greek: κόσμος [Alm. Heiberg: I.4, 16:1. – PH Heiberg: I.4:1, 74:27]