(computing) A slot for additional hardware, cards, etc. for the purpose of expanding a computer system.

plural of expansion slot

(construction) A structural separation between two building elements that allows free movement between the elements without damage to the system.

(roofing) A cleat designed to accommodate thermal movement of metal roof panels.

plural of expansion pack

(computing) A module that adds new content to an existing piece of software. / (video games, by extension) An add-on for a video game that includes additional content and is typically sold separately.

plural of macro expansion

(physics) The cooling of a gas as it undergoes adiabatic expansion

(computing) The source code (assembler or other language) created by interpretation of a macro

plural of expansion adapter