trajectory

From Modern Latin trajectorium, from trajectorius (“of or pertaining to throwing across”), from Latin traiectus (“thrown over or across”), past participle of traicere, from Latin trans (“across, beyond”) (see trans-) + icere, combining form of iacere (“to throw”) (from PIE root *ye- "to throw, impel"). Middle French and Middle English had trajectorie as "end of a funnel", from Latin traiectorium.

• IPA^(key): /tɹəˈdʒɛktəɹɪ/

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trajectory (plural trajectories)

1. (astronomy, space science) The path of a body as it travels through space.
2. (cybernetics) The ordered set of intermediate states assumed by a dynamical system as a result of time evolution.
3. (figuratively) A course of development, such as that of a war or career.
   • 2013 March 1, Harold J. Morowitz, “The Smallest Cell”, in American Scientist‎, volume 101, number 2, page 83:

     It is likely that the long evolutionary trajectory of Mycoplasma went from a reductive autotroph to oxidative heterotroph to a cell-wall–defective degenerate parasite. This evolutionary trajectory assumes the simplicity to complexity route of biogenesis, a point of view that is not universally accepted.

• (astronomy, space): flyby trajectory

• (cybernetics): run