Ink is a pigmented liquid or paste used for writing and printing. It comes in different colors, but the most common type is black. Ink can be made from natural sources such as soot or charcoal or synthetic materials. The word "ink" has multiple meanings, including a dark liquid ejected by some cephalopods for protection, such as the octopus and squid. Additionally, it can refer to the act of marking, coating, or staining with ink. In informal language, inking can also refer to appending one's signature to a contract. The word "ink" has origins in Old French enque, Late Latin encaustum, Greek enkauston, and enkaiein. These words all have their own unique meanings and origins that are worth exploring.