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li·bra·tion

(lī-brāshən)

A slight rotational oscillation, real or apparent, of a satellite such as the moon, as viewed from the larger celestial body around which it revolves.

[Latin lībrātiō, lībrātiōn-, oscillation, from lībrātus, past participle of lībrāre, to balance, from lībra, balance.]

librate′ (lībrāt′) v.

li·bration·al adj.

libra·to′ry (-brə-tôr′ē) adj.

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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