Even

As an adjective, 'even' means flat, smooth, or equal, like an even surface or an even score. As an adverb, it emphasizes something surprising or extreme, as in 'He didn’t even call.'

It comes from Old English 'efen', meaning 'level, equal, like'. The idea of flatness and equality later stretched into time and number meanings, like 'even numbers' and 'evenly matched'.