A software module that extends or enhances the capabilities of an existing application.

synoniem: plug-in.

Nederlands: insteekkaart, uitbreidingskaart, kaart
Pools: karta, wtyczka, plug-in, plugin

A component that is added to something to improve it.

synoniemen: addition, improver.

A supplementary component that improves capability.

synoniemen: accessory, appurtenance, supplement.

Nederlands: hulptoestel
Pools: akcesorium, dopełnienie, dodatek, uzupełnienie