noun, plural tra·jec·to·ries.

the curve described by a projectile, rocket, or the like in its flight.
Geometry. a curve or surface that cuts all the curves or surfaces of a given system at a constant angle.

Origin of trajectory

1660–70; < New Latin trājectōria, noun use of feminine of Medieval Latin trājectōrius cast-ing over. See traject, -tory1
Related formstra·jec·tile [truh-jek-til, -tahyl] /trəˈdʒɛk tɪl, -taɪl/, adjectivetra·jec·tion [truh-jek-shuh n] /trəˈdʒɛk ʃən/, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for trajectory

path, curve, orbit, direction, flight, track, route, flow, trail, range, line, movement

Examples from the Web for trajectory

Contemporary Examples of trajectory

Historical Examples of trajectory

  • It was just at the second when it reached the top of its trajectory and started to fall.

    High Adventure

    James Norman Hall

  • What we retain of the movement of the mobile T are positions taken on its trajectory.

    Creative Evolution

    Henri Bergson

  • But the rest of his mind tried to imagine such a trajectory.

    Talents, Incorporated

    William Fitzgerald Jenkins

  • Some pitched into the hospital forty yards away, their trajectory just above us.

    The Secrets of a Kuttite

    Edward O. Mousley

  • The greater the velocity, the flatter the trajectory becomes.

British Dictionary definitions for trajectory


noun plural -ries

the path described by an object moving in air or space under the influence of such forces as thrust, wind resistance, and gravity, esp the curved path of a projectile
geometry a curve that cuts a family of curves or surfaces at a constant angle
Derived Formstrajectile (trəˈdʒɛktaɪl), adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for trajectory

1690s, from Modern Latin trajectoria, from fem. of trajectorius "of or pertaining to throwing across," from Latin traiectus "thrown over or across," past participle of traicere "throw across," from Latin trans- "across" (see trans-) + icere, combining form of iacere "to throw" (see jet (v.)). Used in Late Latin and Middle English to mean "a funnel."

Online Etymology Dictionary, © 2010 Douglas Harper

trajectory in Science



Physics The line or curve described by an object moving through space.
Mathematics A curve or surface that passes through a given set of points or intersects a given series of curves or surfaces at a constant angle.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.