Real Dictionary

change
countable noun: A change of clothes is an extra set of clothes that you take with you when you go to stay somewhere or to take part in an activity.
singular noun: If you say that something is a change or makes a change, you mean that it is enjoyable because it is different from what you are used to.
variable noun: If there is a change in something, it becomes different.
verb: If you change from one thing to another, you stop using or doing the first one and start using or doing the second.
verb: To change something means to replace it with something new or different.
verb: When something changes or when you change it, it becomes different.
verb: When you change a baby or change its nappy or diaper, you take off the dirty one and put on a clean one.
verb: When you change a bed or change the sheets, you take off the dirty sheets and put on clean ones.
verb: When you change buses, trains, or planes or change, you get off one bus, train, or plane and get on to another in order to continue your journey.
verb: When you change gear or change into another gear, you move the gear lever on a car, bicycle, or other vehicle in order to use a different gear.
verb: When you change your clothes or change, you take some or all of your clothes off and put on different ones.

change in American English
to put or take (a thing) in place of something else; substitute for, replace with, or transfer to another of a similar kind
intransitive verb: to become different
transitive verb: to make the form, nature, content, future course, etc., of (something) different from what it is or from what it would be if left alone

change in British English
verb: to make or become different; alter

change in Retail
noun: Change is the amount of money handed back to a customer when they have paid with bills or coins that total more than the amount due.