GM Daniel- lightning is a L2 (layer 2) on the Bitcoin (L1… Internet L0) network. Lightning is like the name, super fast for transactions of smaller amount(s). A 100m satoshis is equal to 1 Bitcoin (1 BTC). Zaps are Nostr satoshis. People can Zap you Sats (satoshis) for a note they might like or value (music, art, a picture, specific information, etc). Have a good day!