"pertaining to or according to the rules of arithemetic," 1540s; see arithmetic + -al (1). In modern use, opposed to geometrical. Related: Arithmetically (late 15c.).
Entries linking to arithmetical
arithmetic n.
"art of computation, the most elementary branch of mathematics," mid-13c., arsmetike, from Old French arsmetique (12c.), from Latin arithmetica, from Greek arithmetikē (tekhnē) "(the) counting (art)," fem. of arithmetikos "of or for reckoning, arithmetical," from arithmos "number, counting, amount" (from PIE *erei-dhmo-, suffixed variant form of root *re- "to reason, count").
The form arsmetrik was based on folk-etymology derivation from Medieval Latin ars metrica; the spelling was corrected early 16c. in English (though arsmetry is attested from 1590s) and French. The native formation in Old English was tælcræft, literally "tell-craft."
-al 1
suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).
geometrical adj.
late 14c., from Latin geometricus "of geometry" (from geometria; see geometry) + -al. Since 16c. it has been opposed to arithmetical in ratio, proportion, etc., reflecting the fact that problems of multiplication formerly were dealt with by geometry, not arithmetic. Related: Geometrically.