What is sock? What is sock? A short stocking reaching a point between the ankle and the knee.Meteorology A windsock.A light shoe worn by comic actors in ancient Greek and Roman plays. Comic drama; comedy: "He . . . knew all niceties of the sock and buskin” ( Byron). To provide with socks.sock away Informal To put (money) away in a safe place for future use.sock in To close to air traffic: fog that socked in the airport. To hit or strike forcefully; punch.To deliver a blow.A hard blow or punch.sock it to (someone) Slang To deliver a forceful comment, reprimand, or physical blow to someone else.