召し上がる
めしあがる · meshiagaru · JLPT N4 · verb-godan
-- honorific form of 食べる (たべる) and 飲む (のむ) --
🍚🍵 召す (honorific take in) + 上がる (rise) = the meal goes up to an honoured guest
召す is a respectful verb for eating, drinking and wearing; 上がる adds a second layer of elevation. Meshi also happens to sound like 飯, a plain word for a meal. Use it only for someone else's eating or drinking, never your own.
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.