TL'DR
Smart Contract is in short part of ethereum block chain that lets you trade, transfer funds, exchange money without hassle bypassing agents, contractors, realtors, bankers entirely.
Current structure:
House you like => realtor gets involved=>bank loans you money=> mortgage fees == $5
Structure with ethereum:
House you like => etherum smart contract =>bank loans you money=> no mortgage fees == $1
Watch below for more in depth idea of how smart contracts work:
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