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The Usage Panel is a group of nearly 200 prominent scholars, creative writers, journalists, diplomats, and others in occupations requiring mastery of language. Annual surveys have gauged the acceptability of particular usages and grammatical constructions.
a. Of, relating to, or resembling the earth's equator.
b. Relating to conditions that exist at the earth's equator:equatorial heat.
2. Being or having a mounting with two perpendicular axes, one of which is parallel to the earth's rotational axis, allowing a telescope so mounted to track a celestial object for long periods with adjustments only to that axis.
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.