restrict, treaty, approximate

約 is composed of 糸 (silk) and 勺 (spoon). 糸 represents silk thread, while 勺 refers to a scooping ladle—a vessel with small capacity that conveys the idea of gathering and binding together. Thus, 約 conveys the concept of pulling items together and binding them tightly with thread. Its original meaning is to restrict or restrain, which later extended to denote an agreement or an approximation.