early 14c., also gemetrie, gemetry, from Old French geometrie (12c., Modern French géométrie), from Latin geometria, from Greek geometria "measurement of earth or land; geometry," from combining form of gē "earth, land" (see Gaia) + -metria "a measuring of" (see -metry). Old English used eorðcræft "earth-craft" as a loan-translation of Latin geometria.

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.

"one skilled in geometry," late 15c., from Latin geometres (in Late Latin also geometra), from Greek geometres "land-measurer" (see geometry).

*mē-, Proto-Indo-European root meaning "to measure." Some words may belong instead to root *med- "to take appropriate measures."

It might form all or part of: amenorrhea; centimeter; commensurate; diameter; dimension; gematria; geometry; immense; isometric; meal (n.1) "food, time for eating;" measure; menarche; meniscus; menopause; menses; menstrual; menstruate; mensural; meter (n.1) "poetic measure;" meter (n.2) unit of length; meter (n.3) "device for measuring;" -meter; Metis; metric; metrical; metronome; -metry; Monday; month; moon; parameter; pentameter; perimeter; piecemeal; semester; symmetry; thermometer; trigonometry; trimester.

It might also be the source of: Sanskrit mati "measures," matra "measure;" Avestan, Old Persian ma- "to measure;" Greek metron "measure," metra "lot, portion;" Latin metri "to measure."

1610s, from Hebrew gematriya, a transliteration of Greek geometria (see geometry). "[E]xplanation of the sense of a word by substituting for it another word, so that the numerical value of the letters constituting either word is identical" [Klein].

1650s in geometry, in reference to conic sections, from Modern Latin parameter (1630s), from Greek para- "beside, subsidiary" (see para- (1)) + metron "measure" (from PIE root *me- (2) "to measure").

A geometry term until late 1920s when it began to be extended to "measurable factor which helps to define a particular system," hence the common meaning (influenced by perimeter) of "boundary, limit, characteristic factor," common from 1950s. Related: Parametric; parametrical.

"of, pertaining to, or of the nature of mathematics," early 15c., from Medieval Latin mathematicus "of or belonging to mathematics," from Latin mathematica (see mathematic) + -al (1). Also, by 1765, "pertaining to the quadrivium," comprising arithmetic, geometry, astronomy, and music. It also could include optics. Related: Mathematically.

The four mathematical arts are arithmetic, geometry, music, and astronomy; these anciently were termed the quadrivium, or fourfold way of knowledge. [Sir John Hawkins, "A General History of the Science and Practice of Music," Sir John Hawkins, 1776]

1560s, in geometry, "plane figure contained by a right angle and a part of a circumference of a circle," from Latin segmentum "a strip or piece cut off, a cutting, strips of colored cloth," from secare "to cut" (from PIE root *sek- "to cut"), with euphonious alteration of -c- to -g- before -m-.

Latin segmentum was used in Medieval Latin as a geometry term, translating Greek tmema. The meaning "segmental portion of anything circular" is from 1640s; the general sense of "a division, section, part cut off or marked as separate from others" is from 1762.

in geometry, "a non-equilateral oblique parallelogram," 1560s, from French rhomboide or directly from Late Latin rhomboides, from Greek rhomboeides "rhomboidal; a rhomboid;" see rhomb + -oid. Related: Rhomboidal. As an adjective, "having a form like a rhomb," from 1690s.

1580s as one of the three fundamental functions of trigonometry, from tangent (adj.). From 1650s in geometry as "a tangent line, straight line through two consecutive points of a curve or surface." The figurative suggestion of flying off on a tangent is from 1771.