DEC, dec or Dec may refer to:
The decibel (dB) is a logarithmic unit used to express the ratio of two values of a physical quantity.
This article deals with decision-making as analyzed in psychology. See also Decision theory.
Decapitation (from Latin, caput, capitis, meaning head) is the complete separation of the head from the body.
Deconstruction is a name commonly associated with philosopher Jacques Derrida's critical outlook over the relationship between text and meaning.
Decompression sickness (DCS; also known as divers' disease, the bends or caisson disease) describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurisation.
Decentralization is the process of redistributing or dispersing functions, powers, people or things away from a central location or authority.
Decolonization (US) or decolonisation (UK) is the undoing of colonialism, where a nation establishes and maintains its domination over dependent territories.
The decathlon is a combined event in athletics consisting of ten track and field events. The word decathlon is of Greek origin, from δέκα (déka, meaning "ten") and ἄθλος (áthlos, or ἄθλον, áthlon, meaning "feat").
Deception, beguilement, deceit, bluff, mystification, ruse, and subterfuge is the act of propagating beliefs in things that are not true, or not the whole truth (as in half-truths or omission).