trajectory

American  

[truh-jek-tuh-ree] / trəˈdʒɛk tə ri /

noun

plural

trajectories

1. the curve described by a projectile, rocket, or the like in its flight.

2. Geometry. a curve or surface that cuts all the curves or surfaces of a given system at a constant angle.

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trajectory British  

/ -trɪ, trəˈdʒɛktaɪl, trəˈdʒɛktərɪ /

noun

1. the path described by an object moving in air or space under the influence of such forces as thrust, wind resistance, and gravity, esp the curved path of a projectile

2. geometry a curve that cuts a family of curves or surfaces at a constant angle

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trajectory Scientific  

/ trə-jĕk′tə-rē /

1. Physics The line or curve described by an object moving through space.

2. Mathematics A curve or surface that passes through a given set of points or intersects a given series of curves or surfaces at a constant angle.

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Usage

What does trajectory mean? The trajectory of an object is the path it follows once in flight or in motion. The word is especially used in the context of the path of projectiles like rockets, but it can be used in many different contexts. The trajectory of a golf ball is the curved path it follows in the air after being hit by a golf club. The trajectory of an asteroid is the path it follows in space. The potential trajectory of a storm is the route that it may travel. In geometry, trajectory is used in a more specific way to refer to a curve that intersects through a series of points at the same angle. Example: Try to determine the trajectory of the ball as it flies through the air so you can position yourself to catch it.

Other Word Forms

• trajectile adjective
• trajection noun

Etymology

Origin of trajectory

First recorded in 1660–70; from New Latin trājectōria, noun use of feminine of Medieval Latin trājectōrius “casting over”; equivalent to traject + -tory ¹

Explanation

If you stay on your current trajectory of constant shopping, dining out, and yacht rentals, you'll end up broke. A trajectory is the path of an object through space, or the path of life that a person chooses. Trajectory comes from the Latin trajectoria, which means "throw across." The prefix tra- is short for trans-, which means "across" (think transport and transit) and the ject comes from jacere, which means "throw" and is also the root of the word jet. If you wanted to describe the path of a jet through the sky, you could refer to the jet's trajectory.

Example Sentences

"But they offer a trajectory for improvement. We need to continue to improve on multiple areas -- materials, circuits and packaging -- to make this technology ready for data center applications."

From Science Daily • Apr. 10, 2026

Investors should evaluate whether current multiples price in the growth trajectory or leave room for further appreciation.

From MarketWatch • Apr. 8, 2026

Two of the three planned course corrections on the way to the Moon were scrapped because the trajectory was already so accurate they were not needed.

From BBC • Apr. 7, 2026

The Orion capsule carrying the astronauts will now travel back to Earth in a so-called free-return trajectory before coming down in the ocean.

From Barron's • Apr. 7, 2026

It swung from a wire that was sixty-seven meters long; because its trajectory changed over time, he explained, it proved beyond all doubt that the earth rotated.

From "All the Light We Cannot See" by Anthony Doerr

Related Words

• curve
• orbit
• path