serum
SEER-uhm
/ˈsɪə.rəm/
A lightweight, highly concentrated liquid cosmetic or medical formulation designed to deliver active ingredients deep into tissues.
In cosmetics, serums are thin and fast-absorbing compared to thick creams or lipid ointments.
The story behind the word. In ancient Latin, 'serum' was the thin watery fluid left behind when milk curdled into cheese. Early biological sciences used it for clear fluid separating from blood clots, and cosmetics adopted it for light, water-like fluid formulas carrying active compounds.
Word relationships
- elixir: Elixir carries poetic or mystical overtones of magic potions, whereas serum is precise, chemical, and dermatological.
Commonly confused with
- lotion: Lotion is a thicker emulsion designed for surface moisturization, whereas serum is liquid and highly concentrated with active molecules.
Word family
- serous (adjective): Resembling or producing serum; watery.
Collocations
- facial serum
- vitamin C serum
- hydrating serum
- blood serum
Example sentences
- "She applied a few drops of hyaluronic acid serum before applying her daily cream." Skincare application
- "Blood serum contains proteins, antibodies, and nutrients separated from clotting factors." Medical science
Memory hook
SERUM sounds like CLEAR RUM: a thin liquid packed with concentrated active ingredients. Concentrated liquid active fluid.
When not to use
Do not use inter-changeably with heavy creams or thick oils.
Fun facts
- In immunochemistry, anti-snake venom is called antivenom serum because it is derived from animal blood plasma containing concentrated antibodies.
Related words
Also appears in
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