  Understanding and defining the meaning of "action" is substantial for
robotics research. This becomes utterly evident when aiming at equipping
autonomous robots with robust manipulation skills for action execution.
Unfortunately, to this day we still lack both a clear understanding of the
concept of an action and a set of established criteria that ultimately
characterize an action. In this survey we thus first review existing ideas and
theories on the notion and meaning of action. Subsequently we discuss the role
of action in robotics and attempt to give a seminal definition of action in
accordance with its use in robotics research. Given this definition we then
introduce a taxonomy for categorizing action representations in robotics along
various dimensions. Finally, we provide a systematic literature survey on
action representations in robotics where we categorize relevant literature
along our taxonomy. After discussing the current state of the art we conclude
with an outlook towards promising research directions.
