上旬
shàng xún · HSK 7
first third of a month
📅 上 = upper/first + 旬 = ten-day period; the first ten-day stretch of a month
旬 splits a month into three xún of about ten days each. 上 (upper) marks the first one, so 上旬 covers days 1 to 10. The later thirds are 中旬 (middle) and 下旬 (lower).
上 — horizontal line above a baseline
上 is an indicative character (指事): a short stroke placed above a longer reference line shows the concept of 'above' or 'up'. The earliest oracle-bone forms used two horizontal lines for this; the modern shape added a vertical stroke for clarity. The core meaning of 'upper, above, to ascend' has stayed stable for millennia.