Internationalization (i18n) - The process of designing a software application so that it can be adapted to various languages and regions without engineering changes.
localization (L10n) - The process of adapting software for a specific region or language by adding locale-specific components and translating text.
globalization (g11n) / Native Language Support (NLS) - The combination of internationalization and localization.
Locale - A set of parameters that defines the user's language, country and any special variant preferences that the user wants to see in their user interface.
Localizability (L12y) - The degree to which a software product can be localized.
Resource - Part of a program which can appear to the user or be changed or configured by the user, and this is the data of the program, opposed to its code.
Core product - The language independent portion of a software product.
* Mozilla Internationalization & Localization Guidelines