隆 appears in many compounds: 兴隆 (prosperous), 隆重 (grand; solemn), 隆隆 (rumbling sound). It is also common in names, such as the Qing-dynasty reign title 乾隆.
register
In the onomatopoeic word 轰隆 (a loud rumble or boom) the character takes a first-tone reading, lōng. This is a sound-effect variant of the same rumbling sense; everywhere else the character is read lóng.
Left radical 阝 (the side-form of 阜, mound). Marks 隆 as something rising up from the earth, a hill or swell. Same left 阝 anchors the high-ground family 陡 (steep), 陵 (hill), 阶 (steps), 险 (dangerous terrain).
Top-right 夂 is a downward-pointing foot, here showing motion or descent. In 隆 it sits above the level mark and 生 below, contributing the sense of stepping or rising motion.
Single horizontal stroke beneath 夂, an abstract level marker showing the ground or threshold. Pins the foot 夂 above and the growing form 生 below into a vertical landscape, reinforcing the rising-up image.
Bottom 生 supplies most of the sound (shēng to lóng, a drift in the rounded series) and the meaning of growing upward. A sprout pushing through the ground combines with the hill radical 阝 to give the modern senses lofty, grand, prosperous, swelling.
