It stands for Web of Trust you can learn more about it by checking out nostr:npub1utx00neqgqln72j22kej3ux7803c2k986henvvha4thuwfkper4s7r50e8  n his notes nostr:note1h55unu255jjlmtqz764knc90ergss9y9tk26en34kk2yz6fyzvzsfsp4h5