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.

le segment issu de son centre jusqu'à sa circonférence‘radius’

French

References: PH Morelon: I.8:1, 26:3-4
Translation of:
Arabic: الخطّ الخارج من مركز (الدائرة) إلى الخطّ المحيط بها [PH Morelon: I.8:1, 27:3]
Synonyms:
rayon[PH Morelon: I.9:3, 28:14]