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.

---

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

---

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.

---

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

While Aang’s saga follows the trajectory of Western fantasies that revolve around a Chosen One, his stubborn insistence on nonviolence and befriending perceived enemies reflects Miyazaki’s reverence for empathy, innocence and life’s natural beauty.

From Salon • Jul. 8, 2026

And Petra Capital Management's Albert Yong said the plunge suggests "investors might have already priced in solid results and are increasingly focused on the longer-term trajectory of the memory cycle".

From Barron's • Jul. 7, 2026

“The Bone People” follows the trajectory of a romantic comedy—a woman finds love in a meet-cute, loses that love and, after many travails, finds it again, even better than before.

From The Wall Street Journal • Jul. 6, 2026

“When you look at the earnings trajectory it’s not stopping at all,” yet Nvidia continues to get cheaper.

From MarketWatch • Jul. 2, 2026

Space agencies around the globe—NASA, UKSA, CSA, CNSA, ISRO, CRTS, ROSCOSMOS—release statements assuring citizens that though asteroid 2016BA11’s trajectory will bring it near Earth, it does not pose a threat.

From "We Are the Ants" by Shaun David Hutchinson

Related Words

• curve
• orbit
• path