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tro·choid

(trōkoid′, trŏkoid′)

A curve traced by a point on or connected with a circle as the circle rolls along a fixed straight line.

adj. also tro·choi·dal (trō-koidl, trŏk-oidl)

1. Capable of or exhibiting rotation about a central axis.

2. Permitting rotation, as a pulley or pivot.

[Greek trokhoeidēs, wheellike : trokhos, wheel; see TROCHEE + -oeidēs, -oid.]

tro·choidal·ly adv.

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:

Indo-European Roots

Semitic Roots

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.

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