noun

• A very handsome young man.
• (entomology) Any of several papilionid butterflies of the genus Parnassius, especially Parnassius apollo of Eurasia (also known as the mountain apollo).
• (Greek mythology, Roman mythology) The son of Zeus and Leto (or Jupiter and Latona), and the twin brother of Artemis (or Diana). He was the god of light, music, medicine, and poetry; and prophecy, dance, manly beauty, and more.
• (astronomy) The planet Mercury, when observed as a Morning Star.
• (NASA, space science) A United States space program, and the vehicles it created, used for human travel to the moon.
• (with "the") Apollo Theater, a music hall in New York City associated with African-American performers.
• A butterfly of species Parnassius apollo, a large swallowtail with black and red spots on white wings.
• A male given name
• A placename.
• (astronomy) An asteroid possessing an orbit that crosses the orbit of the Earth and an orbital period of over one year, with semimajor axes greater than 1 AU, and perihelion distances less than 1.017 AU.
• (astronomy) Short for 1862 Apollo, an Apollo asteroid.