18-letter words containing h, i, n, d, e, r
- threatened species — a species likely, in the near future, to become an endangered species within all or much of its range.
- three-day eventing — participation in a three day equestrian competition consisting of dressage, cross-country jumping, and stadium jumping
- transit theodolite — a theodolite having a telescope that can be transited.
- triarylmethane dye — any of the class of dyes containing three aryl groups attached to a central carbon atom: used chiefly for dyeing cotton, wool, and silk.
- under the aegis of — guided or protected by
- urban homesteading — homesteading (def 2).
- water of hydration — the portion of a hydrate that is represented as, or can be expelled as, water: now usually regarded as being in true molecular combination with the other atoms of the compound, and not existing in the compound as water.
- white man's burden — the alleged duty of white colonizers to care for nonwhite indigenous subjects in their colonial possessions.
- white-faced hornet — any large, stinging paper wasp of the family Vespidae, as Vespa crabro (giant hornet) introduced into the U.S. from Europe, or Vespula maculata (bald-faced hornet or white-faced hornet) of North America.
- white-fronted tern — a coastal bird of New Zealand and SE Australia, Sterna striata, with a long black bill, a white breast, and a forked tail
- xenon hexafluoride — a colorless, crystalline compound, XeF 6 , that melts at 50°C to a yellow liquid, and boils at 75°C.