|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|a chattering or flighty, light-headed person.|
|1.||the act or process of determining a sum; addition|
|2.||the result of such an act or process|
|4.||(US) law the concluding statements made by opposing counsel in a case before a court|
|[C18: from Medieval Latin summātiō, from summāre to total, from Latin summa|
summation sum·ma·tion (sə-mā'shən)
The process by which multiple or repeated stimuli can produce a response in a nerve, muscle, or other part that one stimulus alone cannot produce.