On average, around one in every 37 letters in English is a U—or, to put it another way, you can expect U to account for just under three percent of a page of text. As letter frequencies go, that’s not a bad record at all (and places U a respectable 13th out of 26 overall). But of the five full vowels in English, it’s U that’s used the least often, and despite its dictionary entry encompassing all the words in English beginning un– (which accounts for a staggering 1 in 4 of all prefixed words [PDF]), you can expect less than 1.5 percent of the words in a standard dictionary to be listed under U—including the 40 unbelievably unusual and undeniably utilizable U-words listed here.

1. UBIQUIT

Ubique means “everywhere” in Latin, so the verb ubiquit literally means “to become ubiquitous”—or in other words, to seem to appear everywhere.

2. UCALEGON

Ever needed the perfect word to describe a neighbor whose house has burned down? Well, even if you haven’t, that word is ucalegon. It derives from the name of one of the Elders of Troy in Ancient Greek myth, whose house was burned down when the city was sacked by the Achaeans.

3. UGGLE

An old Scots dialect word meaning “to dirty or soil something.” If something is uggsome, incidentally, then it’s ugly looking.

4. UGHTEN

The ughten is the part of the night immediately before daybreak.

5. UGLY-WHISPER

An old Irish English word for a scandalous rumor.

6. UIVIGAR

Derived from an old Scandinavian word for a hedgehog, uivigar is a Scots English word for a sea-urchin—although it’s also used as a byword for anything particularly large and clumsy, or awkwardly shaped.

7. ULLAGE

More often than not used in reference to wine bottles, the amount of empty space between the top of a vessel or container and its contents is called the ullage.

8. ULOTRICHOUS

Derived from a Greek word meaning “woolly”, if you’re ulotrichous then you have tightly-curled hair.

9. ULTRACREPIDARIAN

An ultracrepidarian is someone who talks about or passes judgment on a subject outside of their own area of expertise; to ultracrepidate is to do just that. Both words derive from a story from Ancient Greece (retold in Latin by the Roman scholar Pliny the Elder) in which the renowned Greek artist Apelles happened to have a mistake he had made in a drawing of a shoe in one of his artworks pointed out by a passing cobbler. Apelles thanked the cobbler for his expert contribution and corrected the painting, and, encouraged, the cobbler went on to point out another apparent mistake in the picture. This time, however, Apelles wasn’t quite so grateful, and instead replied, “ne supra crepidam sutor judicaret”—or, “a shoemaker should not judge above the sole.”

10. ULTRAFIDIANISM

Blind, unquestioning faith or credulity.

11. ULTRAMONTANE

Just as ultramarine literally means “beyond the sea,” ultramontane means “beyond the mountains.” As an adjective it can be used to describe anywhere that’s precisely that, but historically it was used to refer specifically to the countries north of the Alps, in north and northwest Europe, particularly in reference to their support for the Pope despite their relative distance from Rome.

12. ULULATE

To howl like a wolf.

13. UMBERSORROW

If you’re umbersorrow then you’re healthy enough to resist falling ill in bad weather.

14. UMBILICIFORM

Something that resembles a navel is umbiliciform, while…

15. UMBILICANIMISM

…is the philosophical practice of staring at your own navel.

16. UMBLE-CUM-STUMBLE

Derived from a deliberate mispronunciation of “understand,” under-sum-stumble was a 19th century slang word meaning “to understand something completely.”

17. UMBLOOK

To umblook is to look about. To umblay is to wrap around something, and to umbfold is to embrace someone.

18. UMBROSOUS

Something described as umbrosous is covered in shadow. Something (or someone) that’s umbriphilous loves being in the shade.

19. UMPLIST

An old word from the far north of Scotland for a sudden shower of rain or gust of wind, an ungasto is a wind that suddenly blows in a different direction.

20. UMQUHILE

An ancient word that still survives in local dialect use, meaning “formerly,” or, “at a previous time.”

21. UNASINOUS

Two or more people who are unasinous are equally stupid.

22. UNBERUFEN

Derived from a German word essentially meaning “unbidden”, unberufen is used in English as an exclamation—like “knock on wood!”—to protect against bad luck or misfortune.

23. UNDER-HONEST

Coined by Shakespeare to mean “less than reliable.” Alongside…

24. UNDER-PEEP

…another Shakespearean invention, literally meaning “to peep out from under something.”

25. UNDER-PINNERS

Victorian slang for your legs. Your upper-storey is your head.

26. UNDERBREET

Sunlight appearing just above the horizon and just below a bank of clouds is the underbreet.

27. UNHECKLED

Long before it meant “to jeer a performer,” to heckle meant “to comb the fibers of a piece of fabric.” So to be unheckled means to be shabbily or untidily dressed.

28. UNIDEXTRAL

If you’re ambidextrous (like James Garfield) then you can use both hands equally well. If you can’t (like most people) then you’re unidextral, and can only use one hand.

29. UNIGRAVIDA

The medical name for a woman in her first pregnancy.

30. UNISTYLIST

A unistylist is a writer who habitually prefers to use the same pen.

31. UNLOVESOME

Horrible or distasteful—the opposite of lovely.

32. UP-DRINKING

A meal or celebratory feast held to mark a woman’s recovery from childbirth.

33. UPAITHRIC

Anywhere described as upaithric has no roof, and is open to the open air.

34. UPBIG

If you’re upbig then you have a very high opinion of yourself.

35. UPCREEPER

A sycophantic, toadying flatterer.

36. UPONLAND

If you’re uponland then you’re in the countryside. Although it’s an Old English word, in the Tudor period the invented name John Uponland or Jock Upaland was used as a byword for any rustic, country-bumpkin character.

37. URANOMANIA

A uranomaniac is someone who believes they have been sent from heaven, or are divinely inspired. A uranophobic is someone who is terrified of heaven.

38. URCEIFORM

If something is urceiform, it is vase-shaped. If it’s unciform then it’s hook shaped, and if it’s unguiform then it’s claw-shaped.

39. URLE

An old northern English dialect word meaning “to draw yourself together when you’re feeling unwell.”

40. UXORIOUS

If uxoricide is the murder of a wife, then someone who is uxorious is especially fond of their wife.