An emission is something that's been released or emitted into the world. Car exhaust, burps, and radio broadcasts are all examples of emissions.

Technically, an emission is anything that's been released out into the open. But more often it refers to gases being released into the air, like greenhouse gasses or emissions from power plants and factories. Anytime your body emits something (sweat, drool, gas), it's also considered an emission. Be careful not to confuse this word with the closely spelled omission — that's something that's been left out.

Definitions of emission

n the act of emitting; causing to flow forth

the act of spreading outward from a central source
discharge, venting
the act of venting
the act (or an instance) of subjecting a body or substance to the impact of high-energy particles (as electrons or alpha rays)
Type of:
egress, egression, emergence
the act of coming (or going) out; becoming apparent

n a substance that is emitted or released

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exudate, exudation
a substance that oozes out from plant pores
transudate, transudation
a substance that transudes
a foul-smelling outflow or vapor (especially a gaseous waste)
a watery discharge from the mucous membranes (especially from the eyes or nose)
vaginal discharge
discharge of secretions from the cervical glands of the vagina; normally clear or white
any of various substances (soluble in water) that exude from certain plants; they are gelatinous when moist but harden on drying
a milky exudate from certain plants that coagulates on exposure to air
Type of:
material, stuff
the tangible substance that goes into the makeup of a physical object

n any of several bodily processes by which substances go out of the body

discharge, expelling
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elimination, evacuation, excreting, excretion, voiding
the bodily process of discharging waste matter
catamenia, flow, menses, menstruation, menstruum, period
the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause
incontinence, incontinency
involuntary urination or defecation
hypermenorrhea, menorrhagia
abnormally heavy or prolonged menstruation; can be a symptom of uterine tumors and can lead to anemia if prolonged
micturition, urination
the discharge of urine
abnormally light or infrequent menstruation
Type of:
activity, bodily function, bodily process, body process
an organic process that takes place in the body

n the occurrence of a flow of water (as from a pipe)

Type of:
flow, flowing
the motion characteristic of fluids (liquids or gases)

n the release of electrons from parent atoms

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an emission of photoelectrons (especially from a metallic surface)
field emission
the emission of electrons that are stripped from parent atoms by a high electric field
photoelectric emission
the release or absorption of quanta above a certain energy level
radiation, radioactivity
the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay
secondary emission
the emission of electrons from a surface that is bombarded by higher energy primary electrons
thermal emission, thermionic emission
the emission of electrons from very hot substances
corpuscular radiation, particulate radiation
a stream of atomic or subatomic particles that may be charged positively (e.g. alpha particles) or negatively (e.g. beta particles) or not at all (e.g. neutrons)
Type of:
a process that liberates or discharges something

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