The word irregardless might not be to everyone’s taste, but there’s no denying that if you were to use it in a sentence, you’d be perfectly understood—and that’s more than enough evidence for it to have been accepted into many dictionaries (albeit flagged as non-standard or informal), including Oxford Dictionaries, Merriam-Webster, and even the hallowed Oxford English Dictionary, which has so far been able to trace it back as far as 1912. So despite it having its origins in an error, and irregardless of what you might think of it, there’s no denying irregardless is indeed a word—and it’s by no means alone.

1. Expediate

Meaning “to hasten” or “to complete something promptly,” the verb expediate is thought to have been invented by accident in the early 1600s when the adjective form of expedite, meaning “ready for action” or “alert,” was misspelled in an essay by the English politician Sir Edwin Sandys (it was later corrected).

2. Culprit

There are several different accounts of the origin of culprit, but all of them seem to agree that the word was born out of a mistake. Back when French was still the language of the law in England in the Middle Ages (a hangover from the days of the Norman Conquest), the phrase Culpable, prest d’averrer nostre bille—literally “guilty, ready to prove our case”—was apparently the stock reply given by the Clerk of the Crown whenever a defendant gave a plea of not guilty. In the court records, this fairly long-winded phrase was often abbreviated just to cul. prit., and, as the Oxford English Dictionary explains, “by a fortuitous or ignorant running together of the two,” the word culprit was born.

3. Despatch

Despatch is a chiefly British English variant of dispatch, often used only in formal contexts like the name of the political despatch box in the House of Commons. The e spelling apparently began as a phonetic variation of the original I spelling, but after Samuel Johnson included it in his Dictionary of the English Language in 1755, its use was legitimized and thrived in the 19th century. Because Johnson himself preferred the I spelling in his own writings, however, it's supposed that he included the e spelling by mistake and inadvertently popularized the error.

4. Nickname

Nicknames were originally called eke names, with the verb eke used here in the sense of “to make longer” or “to provide an addition.” Sometime in the 13th century, however, “an eke-name” was mistakenly interpreted as “a neke-name,” and the N permanently jumped across from the indefinite article an to the verb eke. The same error—known linguistically as “rebracketing” or “junctural metanalysis”—is responsible for nadders, numpires, and naprons all losing their initial Ns in the Middle English period.

5. Ammunition

Ammunition derives from a faulty division of the French la munition, which was incorrectly misheard as l'amonition by French soldiers in the Middle Ages, and it was this mistaken form that was borrowed into English in the 1600s.

6. Scandinavia

Scandinavia was originally called Scadinavia, without the first N, and is thought to take its name from an island, perhaps now part of the Swedish mainland, called Scadia. According to the Oxford English Dictionary, the extra N was added in error by the Roman scholar Pliny the Elder, and has remained in place ever since.

7. Syllabus

If all had gone to plan in the history of the word syllabus, those two Ls should really be Ts: Syllabus was coined as a Latin misreading of an Ancient Greek word, sittybos, meaning “a table of contents.”

8. Sneeze

Oddly, sneeze was spelled with an F and not an S, fneze, in Middle English, which gives weight to the theory that it was probably originally coined onomatopoeically. At least one explanation of why the letter changed suggests that this F inadvertently became an S sometime in the 15th century due to continual misreadings of the long lowercase f as the old-fashioned long S character, ſ.

9. Ptarmigan

The ptarmigan is a bird of the grouse family, found in mountainous and high-latitude environments. Its bizarre name with its initial silent P is something of a mystery, as the original Scots word from which it derives, tarmachan, shows no evidence of it and there’s little reason why one should ever have to have been added to it—except, of course, if it were a mistake. The P spelling first emerged in the late 1600s, and is thought to have been a mistaken or misguided attempt to ally the name to the Greek word for a wing, pteron, and eventually this unusual P spelling replaced the original one.

10. Sherry

Sherry takes its name from the southern Spanish port of Xeres (now Jerez de la Frontera in Cádiz) and was originally known as vino de Xeres, or “wine of Xeres.” This name then morphed into sherris when sherry first began to be talked about in English in the early 17th century, but because of that final S, it didn’t take long for that to be misinterpreted as a plural. Ultimately, a mistaken singular form, sherry, emerged entirely by mistake in the early 1600s.

11. Pea

Another word that developed from a plural-that-actually-wasn’t is pea. One pea was known as a pease in Middle English, but because of that final “s” sound, pease was quickly misinterpreted as a plural, giving rise to a misguided singular form, pea, in the 17th century. The actual plural of pease in Middle English, incidentally, was pesen.

This list first ran in 2016.