membrane

Everyday

1. (science) A very thin layer, like a skin, that covers or lines a part of a living thing or a cell. tree →
2. A thin sheet of material, natural or man-made, that lets some things pass through and stops others. tree →
3. The cell membrane: the thin outer layer around every living cell that controls what goes in and out. tree →

In the lessons

In science, the cell membrane is part of every cell (plant and animal); it lets water, food and oxygen in and waste out. The eardrum is a membrane that vibrates with sound. Inside an eggshell there is a thin membrane. Builders use waterproof membranes under floors and roofs. Phrases: «cell membrane», «thin membrane», «waterproof membrane», «mucous membrane».

Examples

• The cell membrane controls what goes in and out of the cell. tree →
• Peel the egg carefully and you will see a thin membrane under the shell. tree →
• The eardrum is a membrane that shakes when sound hits it. tree →
• A frog has a membrane that covers its eyes underwater. tree →
• Bats' wings are made of a stretchy membrane of skin. tree →
• The builder put a plastic membrane under the concrete to keep out damp. tree →
• Your nose is lined with a wet membrane that traps dust. tree →

Note

Countable noun: a membrane, membranes. Mostly a science word. Do not confuse «cell membrane» with «cell wall»: plant cells have both, animal cells have only a membrane. Spelling: mem-brane (not «membraine»).