Pronunciation: /əbˈzɔːb/ · Part of speech: verb · Related noun: absorption · Field: general medicine / physiology

Definition. To absorb is to take up or soak up something — especially a liquid — into a solid, or more generally to take a substance into a body, tissue, or material. As in the example, “cotton wads are used to absorb the discharge from the wound,” the term often describes the soaking up of fluids, but in medicine it also has an important physiological meaning.

Two main senses in medicine.

• Physical soaking up. In its simplest sense, “absorb” describes a material drawing in a liquid, as a sponge, dressing, or cotton wad takes up fluid. This is why absorbent materials are widely used in wound care and hygiene.
• Physiological uptake. More importantly in medicine, “absorb” refers to the process by which the body takes substances into its tissues and bloodstream. For example, the small intestine absorbs nutrients from digested food, the bloodstream absorbs oxygen in the lungs, and tissues absorb medication so it can act. This biological process is central to nutrition and to how drugs work.

Absorption in the body. When something is absorbed physiologically, it passes from one compartment (such as the gut, lungs, or skin) into the blood or tissues. The efficiency of absorption affects how much of a nutrient or drug actually becomes available to the body — a concept closely related to bioavailability. Many factors influence it, including the surface area available (the small intestine has a vast surface for this purpose), the properties of the substance, and the health of the absorbing tissue.

Clinical relevance. Absorption matters in several ways. Poor absorption of nutrients (malabsorption) can lead to deficiencies and is seen in various digestive disorders. The route by which a drug is given (by mouth, by injection, through the skin) is chosen partly according to how well and how quickly it will be absorbed. And in wound care, the use of absorbent dressings to take up discharge helps keep wounds clean and supports healing.

Distinction from related terms. Adsorb (note the spelling) is a different process, in which a substance adheres to the surface of a material rather than being taken up into it. Assimilate goes a step further than absorb, meaning to incorporate absorbed substances into the body’s own tissues. Secrete and excrete describe the opposite direction — releasing substances out of cells or the body. “Absorb” specifically denotes the taking in of a substance.

Etymology. From Latin absorbere, “to swallow up” or “to suck in” (ab- = away, from + sorbere = to suck in, to swallow).

⚠️ Disclaimer: This explanation is provided for general educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional regarding any clinical questions.