trajectory

noun

tra·​jec·​to·​ry trə-ˈjek-t(ə-)rē 

plural trajectories

1

: the curve that a body (such as a planet or comet in its orbit or a rocket) describes in space

the trajectory of a missile

2

: a path, progression, or line of development resembling a physical trajectory

an upward career trajectory

the nation's economic trajectory

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

Scientists at New York University and Rutgers have proposed that this trajectory may begin in infancy, with early antibiotic exposure being one factor that can initiate a cascade that contributes to Alzheimer’s decades later. — Holly Baines, STAT, 14 Oct. 2026

While import costs have been on a downward trajectory and are expected to continue to fall, protracted geopolitical upheaval will persist in driving up the cost of oil, putting pressure on the industry. — Kate Nishimura, Footwear News, 14 Oct. 2026

This means the trajectory for DAVINCI will require relatively little energy, at least as far as interplanetary missions go. — Stephen Clark, ArsTechnica, 14 Oct. 2026

Following the northward path of the space station's orbit at the time, the rocket flew a trajectory along the United States' East Coast. — Josh Dinner, Space.com, 13 Oct. 2026

Word History

Etymology

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

Rhymes for trajectory

• directory
• refectory
• nectary
• rectory
• subdirectory

Kids Definition

trajectory

noun

tra·​jec·​to·​ry trə-ˈjek-t(ə-)rē 

plural trajectories

: the curve that a body (as a planet in its orbit or a rocket) travels along in space