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.

ὁμαλὴ παραύξησις ‘linear interpolation’

Greek

References: Alm. Heiberg: I.16, 84:22-23
Translated into:
Arabic: تزيد على تساو قدر [Alm. MS Tunis: 18a]
Arabic: الزيادة المساوية [Alm. MS Leiden: f. 14r]
Modern translations:
English: linear interpolation [Alm. Toomer: 73]