A cryptocurrency wallet

A cryptocurrency wallet is a program, application, or physical device that allows you to receive, store, and send digital assets.

 They are of two types: hot and cold.

 Hot wallets are the most popular.  They are widely available online. 

 Cold wallets do not have an internet connection.  They are any portable device, such as flash drives or other external devices, a watch, or even a piece of paper with a private key printed on it.