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.

diametrically opposite‘diametrically opposite’

English

References: Alm. Toomer: 42; 62
Translation of:
Greek: κατὰ διάμετρον [Alm. Heiberg: I.5, 19:24]
Greek: κατὰ διάμετρον τμήματα [Alm. Heiberg: I.12, 64:22]
Synonyms:
(degree) diametrically opposite[Alm. Toomer: 99]
(degree) opposite[Alm. Toomer: 99]
the point diametrically opposite[Alm. Toomer: 62]