1. (noun)absorption, soaking up (chemistry) a process in which one substance permeates another; a fluid permeates or is dissolved by a liquid or solid
2. (noun)absorption (physics) the process in which incident radiated energy is retained without reflection or transmission on passing through a medium "the absorption of photons by atoms or molecules"
3. (noun)assimilation, absorption the social process of absorbing one cultural group into harmony with another
4. (noun)assimilation, absorption the process of absorbing nutrients into the body after digestion