'Teacher' is 'the one who points things out' — from PIE *deyk-. Same root as 'token' and 'digit.'
A person who teaches, especially one employed in a school to instruct others.
From Old English 'tǣcere' (one who teaches), an agent noun from 'tǣcan' (to show, instruct, point out), from Proto-Germanic *taikijaną (to show), from PIE *deyḱ- (to show, point out). The Old English verb 'tǣcan' originally meant 'to show' or 'to point out' before it narrowed to 'to instruct.' The same PIE root produced Latin 'dīcere' (to say, originally 'to point out'), Greek 'deiknýnai' (to show), and Sanskrit 'diśáti' (he points