Wrapped Ether, or WETH, refers to the ERC-20 compatible version of ether. WETH can be created by sending ether to a smart contract where the ether is placed on hold, in turn receiving the WETH ERC-20 token at a 1:1 ratio. This WETH can afterward be sent back into the same smart contract to be "unwrapped" or redeemed back for the original ether at a 1:1 ratio.