18-letter words containing r, y, o
- yellow book cd-rom — A CD-ROM format which is ISO 9660 compliant and uses mode 1 addressing. Discs of this type can be played on most drives and would be appropriate for most multimedia applications which have been developed for personal computers.
- yellow-green algae — a group of common single-celled and colonial algae of the phylum Chrysophyta, having mostly yellow and green pigments, occurring in soil and on moist rocks and vegetation and also as a slime or scum on ponds and stagnant waters.
- 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.
- yerkes observatory — an astronomical observatory located in Williams Bay, Wisconsin, affiliated with the University of Chicago, and having a 40-inch (102-cm) refracting telescope, the largest refractor in the world.
- you never can tell — If you say 'You never can tell', you mean that the future is always uncertain and it is never possible to know exactly what will happen.
- young conservative — a member of the youth section of the United Kingdom Conservative Party
- 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.
- zorrilla (y moral) — Joˈsé (hɔˈsɛ ) ; h^ōseˈ) 1817-93; Sp. poet & playwright