5th earthly branch: 7-9 a.m., 3rd solar month (5th April-4th May), yea
Pictograph of an ancient farming tool. The current meaning is a phonetic loan.
《說文》：“震也。三月陽气動，雷電振，民農時也。物皆生。从乙、匕，象芒達，厂聲也。辰，房星，天時也。从二。二，古文上字。，古文辰。”