add-in 
noun
A device or piece of software that can be added to a computer to give extra features or functions: add-in boards the latest add-ins...
- But the Power Mac is a special case in that its graphics are add-ins, so Apple can pretty much bundle whatever board takes its fancy.
- Certainly, those machines, with their SDMC add-in slot, new peripheral connector and other refinements, will be high on developers' shopping lists - higher, at any rate, than the older PDAs.
- Intel is also known to be working on an add-in that combines Wi-Fi and 3G mobile phone network connectivity, but it is not expected to unveil this product until later this Autumn.
- metallic yarn
- metallide
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- metalliferous
- metallik
- metal-like
- metalline
- metallise
- metalliser
- metallism
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- metallize
- metallizer
- metallocarborane
- metallocene
- metallochrome
- metallochromic
- metalloenzyme
- metallogenesis
- metallogenetic
- metallogenetically
- metallogenic
- metallogeny