吸収
きゅうしゅう · kyuushuu · JLPT N3 · noun
absorption
🧽 吸収 = suck in (吸) + collect (収): pull something in and keep it
吸 means to inhale or suck, as in 呼吸 (breathing). 収 means to gather or take in, as in 収入 (income). So 吸収 is what a sponge does to water, and also what a student does with new knowledge.
吸 — mouth radical 口 + reach 及 (phonetic)
吸 is a phono-semantic compound. The mouth radical 口 signals the meaning—an action done with the mouth—while 及 (jí) hints at the original sound. It depicts drawing air or liquid in through the mouth, giving the modern senses 'inhale, suck, absorb'.