English Reference
noun

trajectory

n.
US /tɹəˈdʒɛktɝi/ UK /tɹədʒˈɛktəɹˌi/ tra·jec·to·ry UK spelling trajectories, trajectory's

  1. 01 B2 Upper Intermediate Science

    the curved path that an object, like a ball or a rocket, follows as it moves through the air or space.

    the path described by an object moving under the influence of gravity or other forces.

    Simple

    The scientists calculated the rocket's trajectory to ensure it would reach the moon safely.

    In context

    The artillery officer adjusted the angle of the cannon to account for wind resistance, ensuring the shell followed a precise trajectory toward the target.

  2. 02 B2 Upper Intermediate

    the way that something changes or develops over time, such as your career or a country's economy.

    a course of development or a sequence of events over time. Often used in professional or economic contexts.

    Simple

    Her career trajectory changed completely after she decided to go back to university.

    In context

    The company's growth trajectory suggests that they will become the market leader within the next three fiscal years.

  3. 03 C2 Proficiency Technical Math

    the set of states a system goes through over time.

    the ordered set of intermediate states assumed by a dynamical system as a result of time evolution.

    Simple

    The computer model showed the trajectory of the weather system over the next week.

    In context

    In chaos theory, even a slight change in initial conditions can result in a wildly different trajectory for the entire system.

Usage follow trajectory

The drive-by shooting that killed rap superstar Tupac Shakur on 7 September 1996 changed the trajectory of hip-hop and elevated the rapper from the face of the genre to a cultural icon.

BBC News· 18 Aug 2026

To turn the trajectory of science around, we need to encourage students to engage with science early.

Phys.org· 17 Aug 2026

From New Latin trāiectōria f (“trajectory”) (used by Newton), the feminine of trāiectōrius (“of or pertaining to throwing across”), from Latin trāiectus (“thrown over or across”), past participle of trāiciō, from trans- (“across, beyond”) (see trans-) + iaciō (“to throw”) (from Proto-Indo-European *(H)yeh₁- (“to throw, impel”)). Middle French and Middle English had trajectorie (“end of a funnel”), from Latin trāiectōrium.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin ine-pro *(H)yeh₁-
Level B2 · Upper Intermediate
Frequency Frequent
Updated