perihelion

noun

peri·​he·​lion ˌper-ə-ˈhēl-yən 

plural perihelia ˌper-ə-ˈhēl-yə 

: the point nearest to the sun in the path of an orbiting celestial body (such as a planet) compare aphelion

perihelial

ˌper-ə-ˈhēl-yəl 

adjective

Examples of perihelion in a Sentence

Recent Examples on the Web

Its nucleus is also far bigger than other notable comets, while its arrival time was fine-tuned to bring it within tens of millions of kilometers from Mars, Venus and Jupiter and be unobservable from Earth at perihelion, along with other unexpected properties. —Hannah Millington, MSNBC Newsweek, 30 Oct. 2025

Scientists are most interested in studying the chemistry of the comet at perihelion, because the gases and dust that come off the comet reveal its composition. —Keith Cooper, Space.com, 29 Oct. 2025

What's happening with 3I/Atlas? Interstellar comet 3I/Atlas is expected to reach perihelion, its closest point to the sun, Wednesday, Oct. 29, according to Space.com. —Jenna Prestininzi, Freep.com, 29 Oct. 2025

When a comet reaches perihelion, the Sun’s heat causes different ices to sublimate into gas. —Chris Young, Interesting Engineering, 27 Oct. 2025

Word History

Etymology

New Latin, from peri- + Greek hēlios sun — more at solar

First Known Use

1666, in the meaning defined above

Rhymes for perihelion

• abelian
• carnelian
• hegelian
• karelian
• aristotelian
• elian

Kids Definition

perihelion

noun

peri·​he·​lion ˌper-ə-ˈhēl-yən 

: the point in the path of a heavenly body (as a planet) that is nearest to the sun