1. Someone who accumulates something in small pieces slowly and carefully; such as, information: Carol was a gleaner who searched through all of the dictionaries and books that she could find for something about the words she was assigned to complete for the dictionary she was working on.
2. Anyone who picks up grain left in the field by a harvester: After cutting the plants in the field with the big farm machine, the farmer's children, Jack and Jill, became gleaners who spent a few hours each day collecting leftover ears of corn in order to avoid wasting any of the maize.