Find the word definition

Wiktionary
domain hack

n. (context computing informal English) An Internet domain name in which the TLD (such as a country code) can be understood as part of the name rather than the usual suffix.

Wikipedia
Domain hack

A domain hack is a domain name that suggests a word, phrase, or name when concatenating two or more adjacent levels of that domain. For example, and , using the fictitious country-code domains .ds and .le, suggest the word birds and example respectively. In this context, the word hack denotes a clever trick (as in programming), not an exploit or break-in (as in security).

Domain hacks offer the ability to produce short domain names. This makes them potentially valuable as redirectors, pastebins, base domains from which to delegate subdomains and URL shortening services.