The pictographs in your keyboard, invented for a Japanese phone carrier in 1999 and mistaken ever since for a word about emotions.
Documented
176 pictures for DoCoMo
Shigetaka Kurita drew the first set, 176 glyphs on a 12 by 12 grid, for NTT DoCoMo's i-mode in 1999. The word is pure Japanese: e, picture, moji, character. MoMA acquired the set in 2016.
Assessment: Documented down to the pixel grid. The etymology is not contested anywhere except in casual speech.
Stories
The emotion coincidence
The universal assumption: emoji means emoticon plus feeling. English speakers hear emotion in it, and no correction sticks, because the false etymology is more useful than the true one.
Assessment: A textbook false friend, documented as false and believed anyway. The archive's core demographic.
Interesting claims
Admissible in court
The modern layer: courts in several countries now weigh emoji as evidence of intent, threat, or contract. A judge deciding what a pistol pictogram meant is doing exegesis, which makes emoji the youngest writing system with case law.
Assessment: Documented in rulings. The archive notes that every writing system ends up in court eventually.
Sources and further reading
Kurita's 1999 NTT DoCoMo set, now at MoMA
Unicode Consortium adoption records
Oxford English Dictionary, emoji, from e plus moji
Court rulings weighing emoji as evidence, Israel 2017 and others
Worth asking
If your thumbs speak a writing system, what does your keyboard say you meant?