Trajectory
truh-JEK-tuh-ree
/trəˈdʒɛktəri/
The path followed by a projectile flying or an object moving under the action of given forces.
It refers to the curved path of an object through space, influenced by gravity and other forces, rather than a straight line or a simple direction.
The story behind the word. The word 'trajectory' comes from the Latin 'trajectus,' the past participle of 'trajicere,' which means 'to throw across.' This verb is formed from 'trans-' (meaning 'across') and 'jacere' (meaning 'to throw'). So, a 'trajectory' is literally the path of something 'thrown across' space. It perfectly describes the curved flight path of a projectile, like a ball or a missile, as it arcs through the air under the influence of gravity.
Word relationships
- path: More general, can be straight or curved, and applies to any movement.
- course: Often implies a planned or intended path, whereas trajectory describes the actual physical path under forces.
- stationery: The state of being still or not moving.
Commonly confused with
- direction: Direction is merely the line along which something moves; trajectory is the entire curved path taken.
Word family
- traject (verb (rare)): to throw or cast across
Collocations
- flight trajectory
- ballistic trajectory
- orbital trajectory
- predict trajectory
- alter trajectory
Idioms & expressions
- on a trajectory to (do something)
Example sentences
- "The physicist calculated the precise trajectory of the satellite, ensuring it would achieve the correct orbit." Physics
- "After the scandal, the politician's career trajectory took a sharp downward turn, from which he never fully recovered." Figurative use
Memory hook
Think of a 'TRAJECTORY' as the path of a 'TRACER' bullet 'JECTED' (thrown) across the sky. Curved Flight Path
When not to use
Do not use 'trajectory' for a simple straight path or a general direction. It implies a specific, often curved, path of a moving object.
Fun facts
- The study of trajectories is fundamental to ballistics and orbital mechanics.
- The term is often used metaphorically to describe the course of a person's career or a trend's development.
Related words
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