tra·​jec·​to·​ry trə-ˈjek-t(ə-)rē How to pronounce trajectory (audio)
plural trajectories
: the curve that a body (such as a planet or comet in its orbit or a rocket) describes in space
: a path, progression, or line of development resembling a physical trajectory
an upward career trajectory

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Formed with part of the prefix trans-, "across", trajectory means a "hurling across". By calculating the effect of gravity and other forces, the trajectory of an object launched into space at a known speed can be computed precisely. Missiles stand a chance of hitting their target only if their trajectory has been plotted accurately. The word is used most often in physics and engineering, but not always; we can also say, for example, that the trajectory of a whole life may be set in a person's youth, or that a new book traces the long trajectory of the French empire.

Examples of trajectory in a Sentence

the trajectory of the missile
Recent Examples on the Web Those rare ball-python traits first discovered in the wild and now known as base morphs had followed this trajectory. Rebecca Giggs, The New Yorker, 19 Feb. 2024 Its trajectory towards a triumphant night on the Dolby Theatre stage on March 10 seems assured. Clayton Davis, Variety, 18 Feb. 2024 This changes the trajectory of his life, spiritually and emotionally. Lynnette Nicholas, Parents, 16 Feb. 2024 After initially joining the team, Scott realized the trajectory his career could take. Shane Connuck, Charlotte Observer, 13 Feb. 2024 Okada said the main mission goal is to put the rocket into the intended trajectory. Mari Yamaguchi, Quartz, 13 Feb. 2024 Once in Earth’s orbit, the lunar lander will separate from the rocket and begin venturing on its own, using an onboard engine to boost itself on a direct trajectory toward the lunar surface. Jackie Wattles, CNN, 12 Feb. 2024 The future trajectory is even worse: Chinese shipbuilding capacity now exceeds that of the U.S. by a factor of 200, according to unclassified data from the Office of Naval Intelligence. Gil Barndollar, TIME, 12 Feb. 2024 Matthew and Rachelle felt mounting unease about Zac’s trajectory. Patrick Radden Keefe, The New Yorker, 5 Feb. 2024 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'trajectory.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


New Latin trajectoria, from feminine of trajectorius of passing, from Latin traicere to cause to cross, cross, from trans-, tra- trans- + jacere to throw — more at jet

First Known Use

1696, in the meaning defined at sense 1

Time Traveler
The first known use of trajectory was in 1696

Dictionary Entries Near trajectory

Cite this Entry

“Trajectory.” Dictionary, Merriam-Webster, Accessed 4 Mar. 2024.

Kids Definition


tra·​jec·​to·​ry trə-ˈjek-t(ə-)rē How to pronounce trajectory (audio)
plural trajectories
: the curve that a body (as a planet in its orbit or a rocket) travels along in space
Last Updated: - Updated example sentences
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