Transaction Confirmation
Formal
Hashing a transaction and adding it to the particular Blockchain successfully. Usually, more than one confirmation is required for the transaction to go through to ensure the transaction is legitimate and not unsupported.
Practical
Each transaction made on a Blockchain needs miners to add it to a block and confirm it. Usually more than one confirmation is required for the transaction to go through to ensure the transaction is legitimate and not unsupported (e.g. sending 2 Litecoins from a wallet that only contains 1 Litecoin).
