trajectory

American  

[truh-jek-tuh-ree] / trəˈdʒɛk tə ri /

noun

• trajectories
  plural

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

Derived Forms

• trajection
  noun
• trajectile
  adjective

Inflected Forms

Nouns

• trajectories
  plural

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

See Examples For:

trajectory trajectories

The shutdown brought that trajectory to a sudden end; average attendance fell by 20% in 1995, meaning 20 million fans had disappeared.

From Los Angeles Times ● Aug. 21, 2026

But the trajectory of Scottish Labour's Holyrood results make for grim reading – they've lost MSPs at every election since 1999.

From BBC ● Aug. 20, 2026

The team hopes that data from two complete orbits will allow them to determine the star's trajectory with enough precision they can also directly measure the black hole's rotation.

From Barron's ● Aug. 20, 2026

Independent astronomers first determined the rocket's trajectory using information that was publicly available.

From Science Daily ● Aug. 20, 2026

I push that memory away and focus on what I know will be the trajectory of my life once I’m done with high school in two years.

From "Split the Sky" by Marie Arnold

More than once, she said, she has had to order planes to slow down or alter their trajectories to avoid accidents.

From Barron's ● Aug. 23, 2026

They remain on very different trajectories, with William's life heading remorselessly to the point where he will take to the throne.

From BBC ● Jul. 4, 2026

In some ways, it’s a journey that mirrors the actors’ own trajectories.

From Los Angeles Times ● Jun. 26, 2026

Those trajectories made them ideal destinations for sample-return missions.

From Science Daily ● Jun. 25, 2026

One picture showed Katherine Johnson sitting at her desk at 1244, pencil in hand, “analyzing lunar trajectories and computing trip time to the Moon and return to Earth by a space vehicle.”

From "Hidden Figures" by Margot Lee Shetterly

Related Words

• curve
• orbit
• path