A cowlick refers to a tuft of hair that sticks up or grows at a different angle than the rest of the hair. The angle is caused by hair growing in a swirling pattern.
The word's usage can be traced back to the 1590s and is a combination of the words "cow" and "lick." It is believed that the word came about because cowlicks look similar to patterns created in a bovine calf's hair after it has been groomed by its mother. Cowlicks often resist being combed flat and are best concealed with the proper hairstyle and use of styling products.