Cygnus [Lat.,=the swan], northern constellation located SE of Draco and NW of Pegasus. It was depicted as a bird by most ancient cultures. It is sometimes called the Northern Cross because five of its brightest stars form a huge Latin cross. Its most famous star is Deneb, at the head of the cross, forming a large triangle with Vega in Lyra and Altair in Aquila. Cygnus reaches its highest point in the evening sky in September.

Cygnus is the Latin word for swan, romanized form of the Ancient Greek κύκνος (kyknos) "swan", it may refer to:

• Cycnus, a character in Greek Mythology
• Cygnus (constellation), a northern constellation and one of Ptolemy's 48 constellations, named after a character in Greek Mythology
• Cygnus X-1, a binary star located within the constellation
• The Cygnus X-1 duology is a pair of epic songs by the progressive rock band Rush, the songs being about a trip to Cygnus X-1
• Cygnus (genus), the genus of most swans
• Cygnus Solutions, a company that provided commercial support for free software and the original developer of Cygwin
• Cygnus spacecraft, a space vehicle under development by Orbital Sciences Corporation
• Cygnus...Vismund Cygnus, a song from The Mars Volta album Frances the Mute
• U.S.S. Cygnus, Dr. Reinhardt's ship in the 1979 Walt Disney movie The Black Hole
• Cygnus Business Media, a U.S.-based business to business publishing company.
• Cygnus (programming language), a general purpose interpreted programming language.
• Cygnus, the drummer for Deadstar Assembly
• , a house in Thorpe St Andrew High School