Hereby/ˌhɪrˈbaɪ/ Definition 1 of 3Pro Tip 1/3Ceremonial Usage Use 'hereby' in formal declarations to indicate the precise moment an action is taken. By the power vested in me, I hereby pronounce you graduates. Pro Tip 2/3Emphasizing Action 'Hereby' emphasizes that something is being done right now, often officially. I hereby accept the terms of the agreement. Pro Tip 3/3Speech Authority It's commonly used by people in authority, like officials, during speeches or announcements. We hereby open the new community center!