What is acceleration measured in?

Calculating acceleration involves dividing velocity by time - or in terms of units, dividing meters per second [m/s] by second [s]. Dividing distance by time twice is the same as dividing distance by the square of time. Thus the SI unit of acceleration is the meter per second squared.

This I what it showed when I looked it up so if your writing this down try and put some in your own words

Acceleration is measured in (distance) per (unit of time) squared; for example, feet/second squared. in the SI (metric) system the official unit is metres/second/second or metres / (second squared).