These two terms seem to have a lot in common, as both of them are used in property transactions for security purposes.
Deposit: a general term for depositing funds to secure transactions without specific provisions as how to apply the money.
Earnest money: a sum paid up front to bind the parties to a sale transaction with specific rules as to how it should be applied if the sales transaction falls through. o keep the property for a certain period exclusively for the payor of earnest. Essentially it does not address the issue of refundability, although it generally is not refundable. It is usually not part of the contract of sale, it is a pre-contract arrangement.
