To tell means to communicate something in words, such as a fact, story, or instruction. It can also mean to recognize or notice something, as in 'You can tell he’s tired.'
It comes from Old English 'tellan' meaning 'to count, reckon, or narrate', related to German 'zählen' meaning 'to count'. Counting and telling stories were once closely linked, both involving careful listing.
The original meaning of 'tell' was closer to 'count', which is why a 'teller' at a bank still counts money. Storytelling is like counting events in order, which might be why our brains love narratives that add up step by step.
Complete word intelligence in one call. Free tier — 50 lookups/day.