aftereffect

n. consequence, byproduct

An afterimage is an optical illusion that occurs after looking away from a direct gaze at an image. This is closely related to the phenomenon called the persistence of vision, which is used in animation and cinema. One of the most common afterimages is the bright glow that seems to float before one's eyes after staring at a light bulb or a headlight for a few seconds.
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Afterimage /af·ter·im·age/ a retinal impression remaining after cessation of the stimulus causing it. af·ter·im·age n. [more]Aftereffect - Community and Resources

Noun
1. any result that follows its cause after an interval
(hypernym) consequence, effect, outcome, result, event, issue, upshot
2. a delayed effect of a drug or therapy; "the drug had unexpected aftereffects"
(hypernym) effect

Synonyms and related words:
afterbirth, afterclap, aftercrop, afterglow, aftergrowth, afterimage, aftermath, afterpain, aftertaste, by-product, consequence, event, eventuality, issue, outcome, placenta, remainder, residual, residuum, result, secundines, side effect, track, trail, upshot, wake,