XUL - XML User Interface Language - The markup that is used to lay out the user interface in Mozilla-based programs
XPI - File format (basically zip) used for Extensions and Themes (themes CAN also use jar which is the same thing but XPI is prefered)
Jetpack - The Mozilla Add-ons SDK which abstracts the API to allegedly make writing extensions simpler.
Bootstrap - A restartless extention or specifically to boostrap.js/cuddlefish. These extensions do not use XUL overlays defined in chrome.manifest.
Overlay - Relates to a process where one XUL file is overlaid over another -OR- a specific style of writing an add-on also referred to as Traditional XUL extension
Fennec - The internal codename for the Android version of the browser
MailNews - The shared back-end components used to provide the core functionality for a mail client such as FossaMail
mozbuild - The python driven build system files for Mozilla programs
MozillaBuild - the toolchain package that contains all you need (except for a compiler such as Visual Studio) to build a Mozilla-based application on WIndows
Australis - The UX style(theme) and a series of technologies in Firefox 29 and higher that are NOT included in Pale Moon.
CustomizableUI - An Australis related technology that allows building UI components purely with javascript via the Add-ons SDK. (This is ALSO not in Pale Moon)
AppMenu - The normally blue "Pale Moon button" that is present when the menu bar is hidden
If there are any other terms you want defined please post them


