The word "nudge" refers to a gentle push or prod, usually with the intention of getting someone's attention or encouraging them to take action. It can be used both in a physical sense, where someone might lightly bump into another person, and in a figurative sense, where someone might encourage or prompt another person to do something in a subtle manner.
The word "nudge" originated in the late 19th century. It is thought to be of uncertain origin, although it may be related to the earlier word "nudge", which may derive from the dialectal word nudg—meaning to push or shove.