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.

نصف الفلك/الدائرة ‘semi-circle’

Arabic

References: Alm. MS Leiden: f. 4v
Translation of:
Greek: ἡμικύκλιον [Alm. Heiberg: I.5, 19:7; I.10, 32:10]
Synonyms:
نصف الدائرة[Alm. MS Tunis: ]
نصف دائرة[Alm. MS Tunis: ]