first month of the lunar year
Depicts a foot (止) going out towards city walls (丁). 丁 also represents the sound. Based on the original meaning "to attack (an enemy)", now written as 征. The meaning of this character has shifted over time and now means "correct".
《說文》：“正，是也。从止，一以止。，古文正，从二，二，古上字。，古文正，从一、足，足者，亦止也。”
to attack (an enemy)