"To ream" in the engineering sense means to make a hole (in a sheet of metal) bigger by shoving something into it. A "reamer" is a long tool, with a hard metal tapered shaft. ...with a bit of creative thinking, you could probably guess how this word gained its informal meaning...

As a noun, 'ream' means 500 sheets of paper. However, it can also be used in the plural 'reams' to mean 'a very large amount' or 'a large quantity of writing': 'reams of work to do'. As a verb, it is used in informal contexts to mean 'to treat sb unfairly or cheat them'.

ماعون ورق او مقدار كبير وهى اسم وفعل

The noun is a stack of paper ready for writing or printing (500 sheet / pieces if you buy it in a office supply store). The verb is to cheat someone or treat them in a bad way. The verb "ream someone out" means to yell at them for something they did wrong or made a mistake.