As a Noun: 1. The side or part of something that is towards the rear or farthest from the front. It is normally not used or seen as much as the front. English = back. 2. Thinking of the future as a time which is in front of you, used to point to that period of time which is before the present and thus ‘behind’ you. English = past. As a Verb or Adjective: 1. To move in a direction which is the opposite direction to the one in which you normally face or in which you normally go when walking or driving. English = go backwards, back up, reverse. 2. To be located at the side or part of something that is towards the rear or farthest from the front. English = (be) at the back of. 3. To move in a direction that takes you to a place where your were before. English = go back. 4. To go back in time to the past. As Modifier: 1. Used after time signs, at the beginning or end of sign phrase, or immediately next to a verb (action) sign to mean the action took place at a time much earlier than the time of speaking or another time given as a of point of reference. English = long ago, in the distant past, back then, long before.