The specified number of blocks added following the publishing of a particular transaction onto a network's blockchain. The threshold or number of blocks deep for a transaction to be considered confirmed may depend on the transaction medium (such as an exchange). Typically Bitcoin transactions need to be six blocks deep for confirmation.
The average amount of time required to add one block to the blockchain. Confirmation time depends on mining difficulty which is regulated by the complexity of the hash algorithm and the number of miners.
A currency pair is a denomination a particular asset is valued. Currency pairs apply to forex, stocks, commodities assets and other financial instruments. Cryptocurrencies are priced in fiat or other digital assets with large market capitalization such as Bitcoin and Ethereum.