1.To bring together into one whole; to collect into one amount; to cast up, as a column of figures; to ascertain the totality of; usually with up. "The mind doth value every moment, and then the hour doth rather sum up the moments, than divide the day."
2.To bring or collect into a small compass; to comprise in a few words; to condense; usually with up. ""Go to the ant, thou sluggard," in few words sums up the moral of this fable." "He sums their virtues in himself alone."
3.(Falconry) To have (the feathers) full grown; to furnish with complete, or full-grown, plumage. "But feathered soon and fledge They summed their pens (wings)."