Simple Definition:
Consumption is the process of using or eating something. It refers to the act of using up resources or goods [resources or items that people need or want]. For example, when you eat food or drink water, you are consuming them. When you buy and use a phone or a pair of shoes, you are also engaging in consumption [using and benefiting from the phone or shoes].
Very Simple Definition:
Consumption is using or eating something. For example, when you eat food or drink water, you are consuming them. When you buy and use a phone or a pair of shoes, you are also engaging in consumption [using them].