Negative Caching
A DNS resolver with negative caching will remember when it is told that a domain does not exist.

When iteratively querying a server in the ancestral line of the record that:

The server will respond with an authoritative negative response. A resolver with negative caching will cache the negative response for a set time period, usually ten minutes. The resolver will reply with a non-authoritative negatives response to the query for that set period

See also:
Caching
TTL