# isthmus

/ˈɪsməs/ (US) · /ˈɪsθməs/ (UK)

Source: https://englishreference.com/word/isthmus
Updated: 2026-08-27

## Senses

### 2. anatomy

noun · CEFR C2 · Technical

a narrow part of an organ or tissue that connects two larger parts.

For teachers: a narrow band of tissue connecting two larger anatomical structures, such as the two lobes of the thyroid gland.

- The doctor explained that the thyroid isthmus connects the two sides of the gland.
- During the surgical procedure, the surgeon carefully separated the thyroid isthmus to gain access to the underlying trachea.

### 3. mathematics

noun · CEFR C2 · Technical

a line in a network that, if removed, breaks the network into two separate parts.

For teachers: an edge in a graph whose deletion increases the number of connected components.

- If this isthmus is removed, the two groups of computers can no longer communicate.
- The algorithm identifies every isthmus in the network to determine which connections are critical for maintaining overall connectivity.

## Examples

- The Panama Canal runs through the narrow isthmus of Panama.
- The isthmus of Corinth in Greece connects the Peloponnese peninsula to the mainland, historically serving as a vital trade route.
- Geologists study how the uplift of the Isthmus of Panama fundamentally altered ocean currents and climate patterns by separating the Atlantic and Pacific oceans millions of years ago.

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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.