n. pl. tra·jec·to·ries
a. The path of a projectile or other moving body through space.
b. A chosen or taken course: "What died with [the assassinated leaders] was a moral trajectory, a style of aspiration" (Lance Morrow).
2. Mathematics A curve that cuts all of a given family of curves or surfaces at the same angle.
[New Latin trāiectōria, from Latin trāiectus, past participle of trāicere, to throw across; see TRAJECT.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.