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.

concentric ‘concentric’

English

References: PH Hamm: I.3:2, 46:18
Translation of:
Greek: ὁμόκεντρος [PH Heiberg: I.3:2, 74:9]
Synonyms:
around the same center[PH Hamm: I.11:7, 56:22]
with the same center[PH Hamm: I.3:3, 46:21]