Yes New England, There is a Difference Between an Isle, Island, and Islet
I don't know about you, but I've never really thought about the difference between an isle, island, or even islet. They're all land surrounded by water. The end. However one of my nieces was excitedly telling me how she learned the differences in school, and was excited to share with me. So, here we go, with additional help from some of my own research.
Clearly the word 'island' is the most common and popular, like Chebeague Island, Maine, Star Island, New Hampshire, Cuttyhunk Island, Massachusetts, Block Island, Rhode Island, and Long Island, New York, which is the biggest island in the lower 48.
Then we have the less common 'isle.' In Maine, we have the Isle au Haut, Cranberry Isles, Matinicus Isle, Deer Isle, and Isle of Shoals (which is also in New Hampshire). There's also Shady Isle in Massachusetts, plus others scattered around New England.
Then there's 'islet.' My niece told me that islets are uninhabitable islands that have little or no vegetation. Basically, it's a huge rock or even sand, according to English Stock Exchange. I see those all of the time on takeoffs and landings at airports near water, don't you? It makes total sense that many aren't named, since they're just part of our topography.
Now, when it comes to 'isle versus island,' most of us think of 'isle' as the more formal or original word. At least I do. Case in point, the British Isles. However, there really is more of difference as English Stock Exchange points out, as well as Collins.
'Isle' is sometimes used as the name of one of many parts of an island or island group. It's almost always used as a proper noun (ex. Isle of Shoals), and is often much, much smaller than an island. Pediaa adds that since it has an old-world, sophisticated side to it, there's a literary significance, too. Many authors and travel writers use it to create a paradise image in the reader’s mind. I so get that. It's definitely more poetic-sounding.
'Island' is the basic, everyday descriptive term. While many islands use the word in their name like those I listed above, most don't, like Nantucket, Martha's Vineyard or, stepping outside of New England for a minute, Hawaii, Japan, and Greenland.
Educational, right? I think it's kind of cool to know these little differences, since we live among so many.