As nouns the difference between islands and isthmus
is that islands is plural of lang=en while isthmus is a narrow strip of land, bordered on both sides by water, and connecting two larger landmasses.
As a verb islands
is third-person singular of island lang=en.
islands
English
Noun
(head)
Verb
(head)
----
isthmus
English
Noun
(en-noun)
A narrow strip of land, bordered on both sides by water, and connecting two larger landmasses.
(anatomy) Any such narrow part connecting two larger structures.
Derived terms
* isthmoid