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Popularized during the 2010s in incel forums. The term gained further popularity in mid-2023 on TikTok after a user created a filter that draws a line showing one's canthal tilt.
Etymology from Wiktionary, CC BY-SA 4.0.
canthal tilt
Today it means: The tilt of a line drawn from the outer corner (the lateral canthus) to the inner corner (the medial canthus) of one's eyes; a lower inner corner is referred to as a positive tilt while a lower outer corner is referred to as a negative tilt. Full definition →