涨
zhàng · HSK 5
to rise (of prices, rivers); to swell
📈 氵(water) + 张 (zhāng, stretch/expand) — water stretching upward = rise
The water radical 氵gives the original sense (water level rising); 张 supplies the sound (zhāng → zhàng) and the idea of stretching/expanding. Extended from rising water to rising prices, swelling, inflating.
涨 — water 氵 + 张 (zhāng, phonetic)
涨 combines the water radical 氵 with 张 (to stretch, expand), which also gives the sound. Originally it described water swelling or rising, like a flooding river. The meaning later extended to prices or quantities going up.