trajectory

trajectory — noun

1. the curved line a moving object makes in the air as it travels from its starting

1.nounB2
Definition

the curved line a moving object makes in the air as it travels from its starting point to where it lands or stops, for example a ball after it is thrown or a rocket after it is launched.

Example

Christopher watched the baseball's high trajectory as it sailed over the fence.

possessive + trajectory: object's trajectory

The rocket's trajectory was carefully calculated by the engineers in Houston.

passive: trajectory was calculated by [agent]

Common collocations
  • flight trajectory
  • ballistic trajectory
  • trajectory of a bullet
  • trajectory of a rocket
  • trajectory of a ball
Synonyms
  • flight path

    more specific to aircraft and missiles; suggests a planned course

  • arc

    emphasises the curved shape of the movement

  • curve

    more general, less technical than trajectory

  • ballistic curve

    technical term for a projectile's unpowered path

Grammar Patterns

trajectory of [something]

possessive + trajectory

Usage Note

This sense always refers to a curved or arched movement through the air, not a straight line on the ground. A train follows a track, not a trajectory.

Common Mistakes

The car drove along a dangerous trajectory through the mountains.
The car drove along a dangerous route through the mountains.
Trajectory is for objects moving through the air, not vehicles on roads.

2. the direction in which a situation, someone's career, or a series of events deve

2.nounC1
Definition

the direction in which a situation, someone's career, or a series of events develops and changes over time, imagined as a course leading to a particular result.

Example

Indra's career trajectory took her from a small startup to a leading technology company.

career trajectory — common noun-noun collocation

The country's economic trajectory has been steadily upward for the past decade.

economic trajectory + upward — adjective + noun + adverb pattern

Common collocations
  • career trajectory
  • economic trajectory
  • upward trajectory
  • downward trajectory
  • change the trajectory
  • set on a trajectory
Synonyms
  • course

    more general; can apply to any direction of movement or development

  • direction

    focuses on the intended or actual end point, not the path

  • progression

    emphasises forward movement step by step

  • path

    less formal; works for both literal and figurative uses

Grammar Patterns

possessive + trajectory

trajectory of [something]

adjective + trajectory

Usage Note

Common in figurative contexts about careers, economies, political movements, and health outcomes. The physical sense (sense 1, PHYSICAL PATH) refers to an actual curved line through air; this sense is metaphorical.

Common Mistakes

The book's story has a confusing trajectory.
The book's plot has a confusing development.
For stories or arguments, use 'development' or 'direction' instead of 'trajectory'.

Synonym discussion

Sense: noun/1

Path is the most general word for any route from one point to another, whether on the ground or through the air, and is the least technical. Course suggests a planned or intended direction, especially for ships, aircraft, or abstract plans. Arc emphasises the curved shape of the movement, like part of a circle, and is less technical than trajectory. Orbit describes a repeated curved path around a larger object, such as a planet around a star, and is specific to space contexts. For example, 'the arc of the thrown ball' focuses on its curved shape, while 'the trajectory of the missile' implies the entire calculated path from launch to impact.

path ↗course ↗arc ↗orbit ↗

Common collocations

Nouns

Adverbs

Phrases

  • the trajectory of [something]
  • on a trajectory toward/to
  • shift the trajectory of

Prepositions

Etymology

LatinNew LatinEnglish

Trajectory comes from New Latin 'trajectoria', from Latin 'traiectus' meaning 'a throw across' — combining 'trans-' (across) and 'iacere' (to throw). The word entered English in the 1600s through physics and astronomy to describe the curved path of objects launched into the air.