• It (pronoun), a third-person neuter pronoun in the English language.
• It (pronoun), fire in the Charrúa language.

As an abbreviation:

• Information technology, a broad subject concerned with aspects of managing and processing information
• it, the ISO 639 alpha-2 short code for the Italian language
• IT, the ISO 3166-1 alpha-2 and FIPS 10-4 country code for Italy
• .it, the Internet country code top-level domain for Italy.
• The IATA code for Kingfisher Airlines and Irtysh Avia
• Institute of Technology, in the educational system of Ireland
• Impulse Tracker, a music sequencer software for MS-DOS
• IEEE Transactions on Information Theory, a scientific journal published by the Institute of Electrical and Electronic Engineers
• Internet television, television distributed via the Internet
• Internal Translator, an early compiler developed by Alan Perlis for the IBM 650 in 1956
• Inclusive Tour, a package holiday that includes accommodation in addition to transportation
• International Times, an underground newspaper in London
• A type of electrical earthing system
• A metalinguistic marker in the Sanskrit grammar of Panini
• A series of enduro motorcycles from Yamaha (e.g. IT175, IT250, IT490)
• Invisibolt Technology, a version of set-through guitar neck join by B.C. Rich

Because it is also the English word it, and many words end with -it, it is commonly used in the construction of domain hack domain names.

There are a number of reserved second-level domain names, for example domain names like italy.it or other names that are referring to geographical regions of Italy.

Templated vector and matrix classes are the core of the IT++ library, making its functionality similar to that of MATLAB and GNU Octave.

IT++ makes an extensive use of existing open source libraries (but not only) for increased functionality, speed and accuracy. In particular BLAS, CBLAS, LAPACK, ATLAS and FFTW libraries can be used.

A few sources claim the film is also known as It! The Vampire from Beyond Space or simply The Terror from Beyond Space, without substantiating evidence.