[ truh-jek-tuh-ree ]
/ trəˈdʒɛk tə ri /

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.

Nearby words

  1. traitress,
  2. trajan,
  3. traject,
  4. trajectile,
  5. trajection,
  6. trakl,
  7. tralee,
  8. trali,
  9. tram,
  10. tram flap

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

Examples from the Web for trajectory

British Dictionary definitions for trajectory


/ (trəˈdʒɛktərɪ, -trɪ) /

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

Science definitions for trajectory


[ trə-jĕktə-rē ]

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.