What does CSS measurement unit em actually stand for

Question

I'm curious as to what the CSS unit "em" actually means. Cm stands for centimetre, for example. I'm not trying to figure out what "em" is or how to utilise it. It appears that the letter "e" in the word "em" refers to the breadth of the letter "M."
Therefore, I'm still unsure of what "em" actually means.

Answer 1

It stands for "emphemeral unit," which refers to the current font size. It is relative to the default font size set in a browser. A font size of 0.875em translates to 87.5% of the browser's default font size.