18-letter words containing t, h, e, d, i
- 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).
- vectorcardiography — a method of determining the direction and magnitude of the electrical forces of the heart.
- vitamin a aldehyde — retinal2 .
- watchdog committee — a committee responsible for monitoring standards of behaviour
- 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.
- wesleyan methodist — a member of any of the churches founded on the evangelical principles of John Wesley.
- 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-footed mouse — any of several North American woodland mice of the genus Peromyscus, especially P. leucopus, having white feet and undersides.
- 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
- white-spotted hyla — a type of tree frog (H. leucophyllata) of tropical America
- widemouth blindcat — any of several catfishes, as Satan eurystomus (widemouth blindcat) of Texas, that inhabit underground streams and have undeveloped eyes and unpigmented skin.