Localisation (or localization in U.S. spelling; also commonly abbreviated L10n) is defined variously, but refers to the adaptation of user interfaces and digital information to the local modes of communication (notably language), culture and standards.

"Localisation is the process by which a product or service is made linguistically and culturally appropriate to a given target locale (country/region and language) where it will be used." (a definition adapted in 2008 from those of W3C and LISA)