Good question!
Satoshis or "sats" are the smallest unit of bitcoin. One bitcoin is divisible to eight decimal places so one satoshi is equal to .00000001 bitcoin which could also be referred to as 1 satoshi or 1 sat.
Following that, 100 million satoshis (100,000,000 sats) are equal to 1 bitcoin.
Satoshis are named after the pseudonymous founder of Bitcoin: Satoshi Nakamoto.