Lightning is a bitcoin technology that accelerates sending and receiving bitcoin (it is ideally near-instant, practically seconds)

A lightning address is one of many ways you can receive bitcoin over lightning.

Most non-technical people get a lightning address by using a wallet app on their phone that supports lightning and lightning addresses.

Once you have a lightning address, you can get "zapped" on nostr, which means someone can signal their enthusiasm for your note (post) by rewarding you with bitcoin, sent over lightning, to your lightning address.