isthmus

Word family

• isthmuses
  nounB2
• isthmian
  adjectiveC1
• isthmic
  adjectiveC2

Synonym discussion

Sense: noun/1

An isthmus is a narrow strip of land connecting two larger land masses, with water on both sides — for example, the Isthmus of Panama joins North and South America. A peninsula, by contrast, is land surrounded by water on three sides and connected to a larger land mass on one side only; Florida is a peninsula, not an isthmus. A strait is the opposite of an isthmus — it is a narrow water passage between two larger bodies of water, such as the Strait of Gibraltar. A causeway is a man-made raised road or track built across low ground or water, whereas an isthmus is a natural land formation. Finally, a channel is a wider body of water connecting two seas or oceans, functioning like a strait but usually broader. Choosing the correct term depends on whether you are describing a land connection (isthmus or peninsula), a water passage (strait or channel), or a man-made crossing (causeway). For example: 'The ship passed through the Strait of Gibraltar' (water) vs. 'The railway runs across the isthmus' (land).

Common collocations

Etymology

The word 'isthmus' entered English directly from Latin 'isthmus', which came from the ancient Greek word 'isthmós' (ἰσθμός), meaning 'a narrow passage, a neck of land'. In ancient Greek geography, the Isthmus of Corinth was simply called 'ho Isthmós'. The same Greek root also carried the sense of a narrow neck or opening in the body, which explains why the word is used in both geography and anatomy. Since the 1500s, English has used 'isthmus' to describe any narrow connecting strip of land, and from the 1800s, medical writers adopted it for narrow anatomical passages.