18-letter words containing s, e, t, l, o, r
- triangle of forces — a triangle whose sides represent the magnitudes and directions of three forces whose resultant is zero and which are therefore in equilibrium
- tristan und isolde — a music drama (composed, 1857–59; première, 1865) by Richard Wagner.
- trobriand islander — a native or inhabitant of the Trobriand Islands of Papua New Guinea
- tufted loosestrife — a primulaceous plant Naumburgia thyrsiflora
- turn in on oneself — to withdraw or cause to withdraw from contact with others and become preoccupied with one's own problems
- turn on one's heel — to turn around abruptly
- two-colour process — (in early colour photography) a method of printing which uses superimposed red and green images
- ulcerative colitis — chronic ulceration in the large intestine, characterized by painful abdominal cramps and profuse diarrhea containing pus, blood, and mucus.
- ultrasonic testing — the scanning of material with an ultrasonic beam, during which reflections from faults in the material can be detected: a powerful nondestructive test method
- ultrasonic welding — the use of high-energy vibration of ultrasonic frequency to produce a weld between two components which are held in close contact
- ultrasound scanner — a device used to examine an internal bodily structure by the use of ultrasonic waves, esp for the diagnosis of abnormality in a fetus
- ur of the chaldees — the city where Abraham was born, sometimes identified with the Sumerian city of Ur. Gen. 11:28, 31; 15:7; Neh. 9:7.
- uriniferous tubule — a urine-bearing tubule in a nephron of a kidney.
- watson-crick model — a widely accepted model for the three-dimensional structure of DNA, featuring a double-helix configuration for the molecule's two hydrogen-bonded complementary polynucleotide strands.
- western alienation — a feeling of resentment by some inhabitants of western Canada against perceived favouritism by the national government towards the eastern provinces
- western isles pony — a breed of large pony, typically grey, with a dense waterproof coat. The only surviving variety is the Eriskay pony
- western meadowlark — any of several American songbirds of the genus Sturnella, of the family Icteridae, especially S. magna (eastern meadowlark) and S. neglecta (western meadowlark) having a brownish and black back and wings and a yellow breast, noted for their clear, tuneful song.
- wireless telephone — Now Rare. radiotelephony.
- wireless telephony — Now Rare. radiotelephony.
- women's liberation — a movement to combat sexual discrimination and to gain full legal, economic, vocational, educational, and social rights and opportunities for women, equal to those of men.
- wrangell mountains — a mountain range in SE Alaska, extending into the Yukon, Canada. Highest peak: Mount Blackburn, 5037 m (16 523 ft)
- zermelo set theory — (mathematics) A set theory with the following set of axioms: Extensionality: two sets are equal if and only if they have the same elements. Union: If U is a set, so is the union of all its elements. Pair-set: If a and b are sets, so is {a, b}. Foundation: Every set contains a set disjoint from itself. Comprehension (or Restriction): If P is a formula with one free variable and X a set then {x: x is in X and P(x)}. is a set. Infinity: There exists an infinite set. Power-set: If X is a set, so is its power set. Zermelo set theory avoids Russell's paradox by excluding sets of elements with arbitrary properties - the Comprehension axiom only allows a property to be used to select elements of an existing set.