A spectral line resulting from the emission of electromagnetic radiation from an atom or other species as it decays from an excited state to one of lower energy.

plural of night emission

An ejaculation or orgasm while asleep, often accompanied by an erotic dream.

plural of nocturnal emission

(uncountable, engineering, acoustics) A phenomenon wherein external stimuli such as mechanical loading generate physical vibrations.

plural of secondary emission

plural of acoustic emission

plural of emissions test

plural of emission line

(physics) A discredited scientific theory, once considered an alternative to special relativity, proposing that light is emitted at speed c relative to its source instead of applying the invariance postulate.