A web service providing wallet functionality: ability to store, send and receive bitcoins. The user has to trust a counter-party to keep the bitcoins secure and be ready to redeem at any time. It is very easy to build a web wallet, so many are prone to hacks. It is not recommended to store large amounts of bitcoins in a web wallet.
Malone, J.A (2015). Glossary of Bitcoin Terms and Definitions. United States: Lulu Press, Inc