18-letter words containing h, o, l, s
- vermilion rockfish — a scarlet-red rockfish, Sebastes miniatus, inhabiting waters along the Pacific coast of North America, important as a food fish.
- wedge-heeled shoes — shoes with wedge heels
- wesleyan methodist — a member of any of the churches founded on the evangelical principles of John Wesley.
- wheelchair housing — housing designed or adapted for a chairbound person
- white-spotted hyla — a type of tree frog (H. leucophyllata) of tropical America
- 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.
- with flying colors — with flying colors, with an overwhelming victory, triumph, or success: He passed the test with flying colors.
- withdrawal symptom — effects of stopping a drug
- world championship — an international competition in a particular sport or activity for people all around the world
- yellow honeysuckle — a spreading, twining vine, Lonicera flava, of the southern and eastern U.S., having fragrant, tubular, orange-yellow flowers.
- yelloweye rockfish — a red rockfish, Sebastes ruberrimus, of waters along the Pacific coast of North America, having eyes that are yellow and possessed of strong, sawlike bony ridges on the head.
- 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.