Word origin · etymology
Chinese jié 節, 'joint, node, section'; in 節氣 jiéqì it names a division of the solar year.
Wiktionary describes 節 as bamboo (竹) with a phonetic part, picturing the node of a bamboo stem and so a segment or boundary, and lists 'solar term' among its senses. The word fits the terms that mark the boundary between one month and the next. No claim is made about when it was first used in this sense.[3]
How we know · epistemology
Astronomical marker with a calendar classification
The instant at which the Sun's apparent longitude reaches a Jie value is calculated, and which of the 24 terms count as month-opening is a calendar convention. The Hong Kong Observatory lists the 24 terms without separating the two kinds, and Wikipedia marks the month-opening terms as the minor ones. The instant rests on the Earth's rotation, which is measured up to now and predicted after, so a term far in the future is less certain to the second.[1][2]
Connected concepts
Sources & provenance
The numbers in the text point to this list; it distinguishes a calculation convention, a historical teaching and an editorial example.