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 (pĕr′ə-hē′lē-ən, -hēl′yən)
n. pl. per·i·he·li·a (-hē′lē-ə, -hēl′yə)
The point in a solar orbit where the orbiting body is closest to the sun.

[Alteration of New Latin perihēlium : peri- + Greek hēlios, sun; see sāwel- in Indo-European roots.]

per′i·he′li·al (-hē′lē-əl, -hēl′yəl) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Astronomy) astronomy of or relating to a perihelion
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
Thus, for any given phase, a perihelial Mercury calls for an exposure less than half that at its aphelion.
Logically speaking, however, Hall's adjusted 'law'--let us call it the Newton--Hall hypothesis--is independently testable of the case of Mercury's perihelial advance, even if there was no test which could then have been conducted of the differences in gravitational forces each predicts.