deuterium; heavy hydrogen

algebra

perfume, cologne

flowers reflected on a mirror and the moon reflected on the water's surface / (by extension, idiomatic) something that is visible but having no substance; illusion, mere shadow, phantom, vision

(mathematics) Fibonacci sequence

Kyūjitai form of 代数学 (“algebra”)

score, grade, mark

aquifer (an underground layer of water-bearing porous stone, earth, or gravel)

algebraic equation (mathematical equation)

mathematician