Tab is a little word with a long history. I looked it up to check on the age of the phrase “keep tabs on” and found that the word itself goes back to Middle English, where it meant “a small strip or flap of material,” interchangeable with tag. From the mid-1400s on, that was the word’s sole meaning for hundreds of years. It began to be used as a verb in  1872, when it simply meant “to affix a tab to something,” again as an alteration of tag.

It wasn’t until the 1880s that tab also took on the meaning of “an account, bill, check,” and this came about, it’s thought, as a shortening of tabulation rather than anything to do with the original word. Or perhaps a shortening of tablet–as in, the paper that you write on. Regardless, this is where my phrase came from. It’s a figurative sense of this tab, but was originally used only in the singular–you would “keep a tab on someone” from about 1890 on.

Tab, as in the key on a typewriter or computer, is from 1916. As a verb meaning “to designate, label, or name,” it’s from 1924.

So in some ways, this word has a downright ancient history…but in other ways, it’s surprisingly modern!