The visible graphical interface features of an application are sometimes referred to as chrome. See Applying custom module chrome for information about how to modify the look of modules (in other words, the module "chrome").

Reference: http://docs.joomla.org/Glossary

The name for a specific piece of language-specific text in a Joomla application.

KEY = Value: where “KEY” is a string to be translated and “Value” is the translated string. In a Joomla program, language keys are used instead of literal language strings. The actual text is substituted at runtime based on the currently active language.