To check something is to look it over, usually to insure that everything has been done correctly. You can also use the verb check out as a synonym for examine. A check is an examination of something to see if it has any flaws.
When you take the SAT, you should check your answer sheet carefully before handing it in. It is easy to fill in the wrong circle which can cause you to lose points on your overall score.
A good mechanic will perform a thorough check of all your car's systems to make sure it is safe for you to drive it.
In a restaurant, a check is the bill for the food you have ordered. Check can also be found in several idiomatic expressions. You can check in to a hotel at the front desk, and you will be given a room. A coat check is someone who takes your coat before you enter a restaurant and gives you a ticket so you can retrieve your coat when you leave. To check your ego at the door means to leave your sense of your own importance behind so you can be open to the ideas of other people.
Part of the check¬in procedure at airports involves a security check. You must take off your shoes and place them along with your carry¬on bag in a tray so they can be xrayed for dangerous items.