The name Memberium is a play on the various hard but light metals used in industry, such as aluminum (aluminium) and titanium. The suffix “ium” is also used to indicate the setting where a given activity is carried out, such as your membership site. An example would be a Gymnasium or Stadium.
We like to think of it as “Member”-“ium”, it’s the raw material you build your website with.
We pronounce it “mem-bayr-ee-um”.
But however you pronounce it, we’ll know what you mean 🙂