Confirmation
Inclusion of a transaction in a network block. The more confirmations, the more reliable the transfer; exchangers usually wait for several before crediting.
In more detail
A confirmation is the inclusion of a transaction in a network block; each next block adds another confirmation and makes the transfer more reliable. Exchangers usually wait for several confirmations before crediting, so funds do not arrive instantly. On a congested network or with a low fee, confirmations take longer to wait for.
