carve, engrave, moment

刻 is composed of 亥 (12th earthly branch) and the radical 刀 (knife). 亥 depicts the skeleton of an animal’s body. Bones are deeply hidden within the flesh and skin, and one must use a knife to cut away the flesh in order to see them. Therefore, 刻 is used to mean to carve or to engrave. In addition, because the ancients used a clepsydra (water clock) to measure time, they would carve marks on the floating arrow to record changes in the water level. From this, 刻 also came to be used as a unit of time.