18-letter words containing e, l, s, i, n, o
- 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
- turn in on oneself — to withdraw or cause to withdraw from contact with others and become preoccupied with one's own problems
- 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
- universal coupling — a coupling between rotating shafts set at an angle to one another, allowing for rotation in three planes.
- uriniferous tubule — a urine-bearing tubule in a nephron of a kidney.
- vermilion rockfish — a scarlet-red rockfish, Sebastes miniatus, inhabiting waters along the Pacific coast of North America, important as a food fish.
- video installation — an art installation incorporating video footage
- video surveillance — a system of monitoring activity in an area or building using a television system in which signals are transmitted from a television camera to the receivers by cables or telephone links forming a closed circuit
- 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.
- wesleyan methodist — a member of any of the churches founded on the evangelical principles of John Wesley.
- 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
- wheelchair housing — housing designed or adapted for a chairbound person
- wild passionflower — the maypop, Passiflora incarnata.
- wilson's phalarope — a phalarope, Phalaropus tricolor, that breeds in the prairie regions of North America and winters in Argentina and Chile.
- 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.
- working men's club — A working men's club is a place where working people, especially men, can go to relax, drink alcoholic drinks, and sometimes watch live entertainment.
- wrangell mountains — a mountain range in SE Alaska, extending into the Yukon, Canada. Highest peak: Mount Blackburn, 5037 m (16 523 ft)