TTL - Time to Live

Time to Live, or TTL, is the number of seconds that a DNS record's information will be cached by the resolving name server. The higher a record's TTL, the longer the information will be cached, and the less queries a client will have to make in order to find the domain.

High TTLs are useful when an administrator wishes to cut down on the number of queries being made to its name server. An administrator will set lower TTLs when making changes to DNS records; this way, it won't take as long for a client's cache to clear, so they view these changes more immediately.