middle-sized

the compound adjective 'middle-sized' is a transparent formation from two english elements. the first element, 'middle', originates from the old english 'middel', itself from proto-germanic midlja-, meaning 'middle, center'. the second element, 'sized', derives from the noun 'size', which entered english from old french 'sise', a shortened form of 'assise' meaning 'assize, regulation, standard measure'. the '-ed' suffix is added to form an adjective meaning 'having a specified size'. the logic of the word is straightforward and descriptive, directly combining the concept of an intermediate position ('middle') with the attribute of physical dimension ('sized') to denote an object of medium or average proportions.

Structure: middle (center) + sized (having a size) middle (from old english 'middel', meaning 'center, intermediate part') + sized (from middle english 'syse', meaning 'size, magnitude', with the suffix '-ed' indicating 'having the quality of')