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.

Unregelmäßigkeit ‘anomaly’

German. – Grammar: n.

References: PH Nix: I.2:3, 73:28-29
Translation of:
Arabic: اختلاف [PH Morelon: I.1:5, 17:5; I.2:3, 17:17]
Synonyms:
Verschiedenheit[PH Nix: I.1:5, 73:1]