OEM vs ODM vs CM

[Daniel Beardsmore]

At the moment, keyboards made by one manufacturer for another are all classified as "OEM" (original equipment manufacturer) keyboards.

However, it looks like this isn't accurate.

My vague understanding is something like: it's OEM if it's a stock keyboard that retains the manufacturer's branding, something else where it's a rebranded reference model (e.g. Alps Bigfoot, a standard Alps product re-badged as various brands), and either an ODM (original design manufacturer) or CM (contract manufacturer) where it's a fully custom product, such as the keyboards Dell orde from Primax, Darfon, Silitek etc and that Apple ordered from NMB and Alps etc.

Does anyone actually have a clear understanding of these divisions, and whether there's a better term that we can use on the wiki instead of "OEM" to cover all these varieties?