Nostr is a protocol. If you are puzzled by that statement, here is an explanation:
nostr:nevent1qqsxymdy9g5xuslt5ypxk6sw8zecn6lwk9fumq6uu6548e5az8kzj6cpz9mhxue69uhkummnw3ezuamfdejj7q3q8ams6ewn5aj2n3wt2qawzglx9mr4nzksxhvrdc4gzrecw7n5tvjqxpqqqqzvv6pckvf