A spectrum is a condition or value that is not limited to a specific set of values but can vary infinitely within a continuum.

Spectrum may refer to:

In physical sciences:

• electromagnetic spectrum
• visible spectrum or optical spectrum, a subset of the electromagnetic spectrum
• emission spectrum observed in light
• absorption spectrum observed in light
• spectral class of stars in Stellar classification
• spectral class of asteroids
• spectral power distribution of an illuminant
• energy spectrum of a collection of particles (particle physics)
• frequency spectrum of a signal
• power spectrum of a signal
• timbre (spectrum of sound energy) of a musical note

In social and medical sciences:

• economic spectrum
• political spectrum of opinion
• spectrum disorder, in psychiatry

In mathematics:

• spectrum (homotopy theory)
• spectrum of a matrix, in linear algebra
• spectrum of an operator, in functional analysis (a generalisation of the spectrum of a matrix)
• spectrum of a ring, in commutative algebra
• spectrum of a C*-algebra
• spectrum of a theory, in mathematical logic
• Stone space of Boolean algebra

In media:

• IEEE Spectrum, a magazine
• NDSU Spectrum, the student newspaper of the North Dakota State University
• Spectrum (magazine), an independent Seventh-day Adventist magazine
• Spectrum (TV channel), a defunct Chicago-area pay television broadcaster founded by United Cable
• The Spectrum (USLS), the student newspaper of the University of St. La Salle in the Philippines

In popular music:

• Spectrum, a band headed by Peter Kember
• Spectrum (band), an Australian group of the 1970s led by Mike Rudd
• Spectrum (album), debut album of fusion drummer, Billy Cobham
• The Spectrum (Sirius), a music channel on Sirius Satellite RadioBuildings
• Spectrum (Montreal), a defunct concert venue and local landmark
• Spectrum London, UK, an art gallery
• Guildford Spectrum, a leisure complex in Guildford, England
• Smith Spectrum, a sports arena in Logan, Utah, U.S.A.
• Wachovia Spectrum, formerly The Spectrum, a sports arena in Philadelphia, Pennsylvania, U.S.A.

Spectrum may also refer to:

• Spectrum (racing car), a series of Australian open wheel racing cars manufactured by Borland Racing Developments
• Spectrum Range, a mountain range in British Columbia, Canada
• Gaylactic Spectrum Awards or Spectrums, a literary award
• Het Spectrum, a Dutch publishing company
• Sinclair ZX Spectrum, an early British home computer