Coin cap in various units.
2,100,000,000,000,000 satoshis.
21,000,000,000,000 Bits.
21,000,000,000 mBTC.
21,000,000 BTC.
Not everyone is aware of Bitcoin's divisibility. They know that they can send like 0.1BTC, but they purely look at it as being one tenth of a coin. I quite often see people state that Bitcoin's fixed 21M coin cap will be a problem when a larger portion of the world will start using Bitcoin on a massive scale. They completely ignore (due to the lack of knowledge) that Bitcoin is easily divisible in plenty of smaller chunks/units. It's a basic thing that everyone should know, but obviously, that's not the case.
This is not known only to those people who never use bitcoin. They generally believe in all sorts of stupidity about the cryptocurrency.