# membrane

/ˈmɛmˌbɹeɪn/ (US) · /mˈɛmbɹeɪn/ (UK)

Source: https://englishreference.com/word/membrane
Updated: 2026-06-20

## Senses

### 1. biological lining

noun · CEFR C1 · Technical

a thin layer of skin or tissue that covers or connects parts of the body.

For teachers: a thin layer of tissue that covers a surface, lines a cavity, or divides a space or organ in an animal or plant.

- The eardrum is a thin membrane that vibrates when sound waves hit it.
- The mucous membrane lining the respiratory tract serves as a primary defense mechanism by trapping inhaled pathogens and particles.

Usage: Often used with 'mucous', 'cell', or 'plasma'.

### 2. synthetic filter

noun · CEFR C1 · Technical

a thin sheet of material used to filter liquids or gases.

For teachers: a thin, semi-permeable material used in industrial or laboratory processes to separate substances in a fluid.

- The water filter uses a special membrane to remove salt from the ocean water.
- Advanced desalination plants utilise reverse osmosis membranes to extract potable water from high-salinity sources with high efficiency.

### 3. historical parchment

noun · CEFR C2 · Archaic · Technical

a single sheet of parchment used in an old scroll or document.

For teachers: a piece of parchment or vellum forming a single leaf or part of a larger roll.

- The historian carefully unrolled the ancient membrane to read the text.
- The medieval tax records were meticulously inscribed across several membranes of sheepskin, which were then stitched together into a continuous roll.

Teaching tip: This sense is rare and restricted to historical or archival contexts; modern speakers use 'sheet' or 'page'.

## Examples

- The cell membrane protects the inside of the cell.
- The waterproof jacket uses a special membrane that lets sweat out but keeps rain from getting in.
- In biological systems, the semi-permeable membrane is essential for maintaining homeostasis by regulating the transport of ions and molecules between the internal and external environments.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.