高～
こう～ · kou～ · JLPT N2 · noun
high
⛰ Compound: kou = high, as in 高校 kou-kou = high school (high + school)
Used as a prefix meaning high or top-level: 高層 kousou = high-rise, 高速 kousoku = high-speed. Same kanji as 高い takai = tall or high.
高 — pictograph of a tall building/tower
高 is a pictograph of a tall structure, likely a watchtower or multi-story gate, with a roof on top, an upper chamber, and a base below. From this concrete image of height it extended to the general meanings 'tall,' 'high,' and figuratively 'lofty' or 'noble.'