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

There is reason to be cautiously optimistic about the trajectory of the current Ebola outbreak in the Democratic Republic of the Congo, the director-general of the World Health Organization said Wednesday. — Helen Branswell, STAT, 16 Sep. 2026

And, thanks to the precision of Roman's SpaceX Falcon Heavy launch vehicle and fuel savings during Roman's early trajectory corrections, the telescope is expected to have enough propellant to operate for the next 22 years. — Josh Dinner, Space.com, 16 Sep. 2026

Haden’s hires failed to return the Trojans to their glory days and eventually sent the program on a downward trajectory. — The Athletic College Football Staff, New York Times, 16 Sep. 2026

Some life plans are only as good as their restructuring, and this is the kind of film that rejoices in the ways meeting someone sets our lives on completely new trajectories. — Zachary Lee, IndieWire, 16 Sep. 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