Mucous or Mucus?

by Craig Shrives
The Quick Answer
Question: What is the difference between mucous and mucus?

Answer: Mucous is an adjective. Mucus is a noun.

Mucous is an adjective meaning producing or secreting mucus.
  • Some mucous membranes are involved with absorption and secretion.
Mucus is a noun which denotes a slimy substance secreted by the mucous membranes and glands.
  • In the human respiratory system, mucus aids in the protection of the lungs.


The adjective mucous means covering or secreting mucus. It is usually seen modifying the nouns gland or membrane. For example:
  • Mucous glands are found in several different parts of the body.
  • Sodium is excreted by all mucous surfaces and by the liver and kidneys.


The noun mucus denotes a slimy substance that is produced by the mucous membranes and glands. For example:
  • Mucus production in humans thickens in cold weather.
  • Nasal mucus is usually clear and thin so it can filter air during inhalation.
Interactive Exercise
Here are three randomly selected questions from a larger exercise, which can be edited, printed to create an exercise worksheet, or sent via email to friends or students.

See Also

adverse or averse? affect or effect? appraise or apprise? avenge or revenge? bare or bear? complement or compliment? dependant or dependent? discreet or discrete? disinterested or uninterested? e.g. or i.e.? envy or jealousy? imply or infer? its or it's? material or materiel? poisonous or venomous? practice or practise? principal or principle? tenant or tenet? who's or whose? What are nouns? What are adjectives? List of easily confused words