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

A little more than a week ago, his campaign was on an upward trajectory.

From Los Angeles Times • Apr. 17, 2026

When drugmakers move away from novel research, the impact may not be immediately visible, but it could shape the trajectory of medical innovation over time.

From MarketWatch • Apr. 15, 2026

They tell clients in a note that EML’s track record of growing its pipeline since fiscal 2024 give them confidence in its medium-term trajectory.

From The Wall Street Journal • Apr. 14, 2026

She said: "Based on the fireball trajectory, the event occurred over the North Sea so, sadly, we do not expect any recoverable meteorites."

From BBC • Apr. 13, 2026

During this time, Acererak managed to kill me twice, mercilessly slamming his winged mount into mine at the perfect trajectory.

From "Ready Player One: A Novel" by Ernest Cline

Related Words

• curve
• orbit
• path