1. fragments or splintered bits.
Noel and Teddy’s discussion about railway safety had Mary picturing us all smashed to smithereens in a train accident.
Synonyms: atoms, bits, crumbs, dabs, dashes, drops, flyspecks, grains, granules, iotas, mites, modicums, particles, pittances, scraps, shreds, smidgens, specks, touches, traces.
* Of course, the singular form of smithereens would be smithereen, but that's not a very useful word. You are welcome to try, but, as of today, no one has answered the question: how can you use smithereen in a sentence.
** According to one source:
Smithereens is an Irish word. It derives from, or is possibly the source of, the modern Irish 'smidirín', which means 'small fragments'. There is a town near Baltimore, close to the south-west coast of Ireland, called Skibbereen. The name means 'little boat harbour' and it is tempting to imagine sailing ships arriving there from the wild Atlantic by being 'blown to Skibbereen'. The more recent 'Troubles' also bring up images of property/people being dynamited and 'blown to Skibbereen' from all over Ireland. There's no record of any such phrase however, and the similarity between the words Skibbereen and smithereens seems to be no more than co-incidence.
Another enticing notion as to the source of smithereens is that it refers to the shards of metal formed when iron is forged and hammered in a smithy. Again, there's nothing but wishful thinking to support that idea. The actual origin is more prosaic. 'Smiodar' means fragments in Irish. 'Een' is a commonplace diminutive ending, as in colleen (girl), i.e. Caile(country woman) + een. Similarly, smiodar + een lead us to smithereen. As with many words that are inherited from other languages, it took some time for the English spelling to become stable. Both 'smiddereens' and 'shivereens' are recorded in the mid 19th century.
The notion of things being 'broken/smashed/blown to smithereens' dates from at least the turn of the 19th century. Francis Plowden, in The History of Ireland, 1801, records a threat made against a Mr. Pounden by a group of Orangemen: "If you don't be off directly, by the ghost of William, our deliverer, and by the orange we wear, we will break your carriage in smithereens, and hough your cattle and burn your house."
['Hough' is a variant of 'hock' - to disable by cutting the tendons]
Smithereens is one of those unusual nouns that, like suds and secateurs, never venture out by themselves - the word is always plural.