Of or relating to emission; sent out or discharged, or characterized by being emitted.
From Latin emissus (sent out) plus the suffix -itious (meaning having the nature of), similar to how words like 'repetitious' and 'expeditious' are formed.
This is one of those English adjectives so rare and technical that you'd only find it in very old scientific texts or specialized medical writing—it's a word that lost its competition to simpler terms like 'emitted.'
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