étoile

Étoile is the French term for a star, used primarily to designate the luminous celestial body that shines in the night sky. The word derives from Latin stella and entered Old French before taking its contemporary form. In everyday language, étoile can also appear in figurative or symbolic contexts, such as in gastronomy or navigation.

In astronomy, an étoile is a massive sphere of hot plasma held together by gravity and powered by nuclear fusion in its core, emitting light and heat. Stars differ from planets and other Solar System bodies in their energy production and composition. They are classified by spectral type, from hottest to coolest as O, B, A, F, G, K, and M, with color correlating to temperature. The Sun is a G-type main-sequence star. Observational properties include apparent magnitude (how bright a star appears from Earth) and absolute magnitude (intrinsic brightness). Stars can be solitary or part of multiple systems and exhibit a range of phenomena such as variable brightness and stellar winds.

Stellar evolution describes the life cycle from birth in molecular clouds to eventual endpoints. A protostar forms as the cloud condenses; when hydrogen fusion begins, the object enters the main sequence. Depending on mass, a star may become a red giant or supergiant and end as a white dwarf, neutron star, or black hole. Lifespans vary from millions to tens of billions of years.

Cultural and linguistic usage encompasses navigation (celestial guiding stars, notably the North Star, or étoile polaire) and symbolism of excellence. In gastronomy, a restaurant may be described as étoilé to indicate Michelin recognition. The term also appears in names, art, and heraldry as a universal symbol of light and guidance.