tra·​jec·​to·​ry | \ trə-ˈjek-t(ə-)rē How to pronounce trajectory (audio) \
plural trajectories

Definition of trajectory

1 : the curve that a body (such as a planet or comet in its orbit or a rocket) describes in space
2 : a path, progression, or line of development resembling a physical trajectory an upward career trajectory

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Did You Know?

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 Last week, health officials offered slightly rosier projections about the trajectory of the virus in L.A. County but cautioned that the improved outlook was contingent on residents’ continuing to practice physical distancing. Los Angeles Times, "A troubling trend: Coronavirus deaths doubled in L.A. County over last week," 27 Apr. 2020 Investors have been focused on the trajectory of the coronavirus for clues as to how pronounced the economic fallout will be. Damian J. Troise,, "Stocks fall as investors brace for earnings hit from virus," 13 Apr. 2020 His nomination speaks volumes about the trajectory of the conservative legal movement—and of the federal courts in the Donald Trump-Mitch McConnell era. Matt Ford, The New Republic, "The Amateurs and Yes-Men in Trump’s Army of Judges," 8 Apr. 2020 But, as Lee shows, cooperation from Chinese capital has helped change this trajectory. Simon Manda, Quartz Africa, "Chinese capital investments in Africa are smaller but more influential than UK or France," 25 Mar. 2020 The latest statistics point to the rapidly changing dynamics in the trajectory of the deadly Covid-19 disease. Jane Li, Quartz, "Coronavirus deaths outside China have surpassed those in China," 16 Mar. 2020 But doubts remained about the true trajectory of the epidemic as China again changed its method of counting and new threats emerged outside the country. Ken Moritsugu, Anchorage Daily News, "New threats emerge outside China in coronavirus outbreak while Chinese voice optimism," 21 Feb. 2020 The Great Inflation, in short, had a major influence on the trajectory of the country. David Beckworth, National Review, "Paul Volcker’s Noble War on Inflation," 16 Dec. 2019 Whether or not that snow materializes depends on the trajectory of a low pressure system now sitting off the Oregon coast. Mike Rogoway, oregonlive, "Portland metro weather: Sunday is cold and wet; it may snow Tuesday night," 24 Nov. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'trajectory.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of trajectory

1696, in the meaning defined at sense 1

History and Etymology for trajectory

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

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Time Traveler for trajectory

Time Traveler

The first known use of trajectory was in 1696

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Statistics for trajectory

Last Updated

12 May 2020

Cite this Entry

“Trajectory.” Dictionary, Merriam-Webster, Accessed 25 May. 2020.

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How to pronounce trajectory (audio)

English Language Learners Definition of trajectory

: the curved path along which something (such as a rocket) moves through the air or through space

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