午：从舂米之杵到日中之时（文物有话说·文物里的汉字）

Group 1 - The character "午" has evolved from its ancient form resembling a grain pounding tool, indicating its historical significance in agriculture and food processing [2][4] - The earliest known grain processing tools were stone grinding plates and sticks, which were later supplemented by the invention of the pestle and mortar to meet increasing agricultural demands [2][3] - Archaeological findings, such as the wooden pestle from the Hemudu site in Zhejiang, demonstrate that the pestle was invented during the Neolithic period, highlighting advancements in food processing technology [3] Group 2 - The coexistence of pestles and mortars with stone grinding tools during the Yangshao culture period provides valuable insights into the development of productivity and living conditions of that era [4] - The character "午" transitioned from representing a grain pounding tool to denoting "midday," with interpretations linking it to the concept of the sun's position and seasonal changes [4]