1.  emission(n = noun.act) emanation - the act of emitting; causing to flow forth;
is a kind of egress, egression, emergence
has particulars: radiation, discharge, venting
Derived forms verb emit₁, verb emit₂

2.  emission(n = noun.substance) discharge - a substance that is emitted or released;
is a kind of material, stuff
has particulars: exudate, exudation, transudate, transudation, effluvium, rheum, vaginal discharge

3.  emission(n = noun.process) - the release of electrons from parent atoms;
is a kind of release
has particulars: photoemission, field emission, photoelectric emission, radiation, radioactivity, secondary emission, thermal emission, thermionic emission

4.  emission(n = noun.process) discharge, expelling - any of several bodily processes by which substances go out of the body; "the discharge of pus"
is a kind of activity, bodily function, bodily process, body process
has particulars: ejaculation, elimination, evacuation, excreting, excretion, voiding, catamenia, flow, menses, menstruation, menstruum, period

5.  emission(n = noun.event) - the occurrence of a flow of water (as from a pipe);
is a kind of flow, flowing

1.  The act of sending or throwing out; the act of sending forth or putting into circulation; issue; as, the emission of light from the sun; the emission of heat from a fire; the emission of bank notes. [1913 Webster]

2.  That which is sent out, issued, or put in circulation at one time; issue; as, the emission was mostly blood. [1913 Webster]

emission, n.
1 (often foll. by of) the process or an act of emitting.
2 a thing emitted.

Etymology:
L emissio (as EMIT)

N  ejection, emission, effusion, rejection, expulsion, exportation, eviction, extrusion, trajection, discharge, emesis, vomiting, vomition, egestion, evacuation, ructation, eructation, bloodletting, venesection, phlebotomy, paracentesis, expuition, exspuition, tapping, drainage, clearance, clearage, deportation, banishment, rouge's march, relegation, extradition, dislodgment, bouncer, chucker-out, vomit, vomitus, puke, barf, emitting, emitted Int, begone!, get you gone!, get away, go away, get along, go along, get along with you, go along with you!, go your way!, away with!, off with you!, get the hell out of here!, go about your business!, be off!, avaunt!, aroynt!, allez-vous-en!, jao!, va-t'en!.

electron emission, emission spectrum, field emission, greenhouse emission, infrared emission, nocturnal emission, photoelectric emission, positron emission tomography, positron emission tomography scanner, radio emission, secondary emission, thermal emission, thermionic emission