18-letter words containing t, d, i, s
- under-registration — the act of registering.
- united arab states — a former (1958–61) federation of the United Arab Republic (Egypt and Syria) and Yemen.
- united nations day — the anniversary of the United Nations on October 24, marking its founding in 1945.
- united states army — the permanent or regular military land force of the United States, under the authority of the Department of Defense since 1947. Abbreviation: USA.
- united states navy — the permanent or regular naval force of the United States, under the authority of the Department of Defense since 1947. Abbreviation: USN.
- university student — a student enrolled in a university
- urban homesteading — homesteading (def 2).
- video compact disc — (storage) (VCD) A storage format used for film distribution.
- video entry system — a security system whereby a person in a building can see someone who wants to gain access by means of a video image
- video installation — an art installation incorporating video footage
- wandering minstrel — travelling performer
- wardrobe assistant — a person who assists the wardrobe mistress in a theatre
- 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.
- white man's burden — the alleged duty of white colonizers to care for nonwhite indigenous subjects in their colonial possessions.
- white-footed mouse — any of several North American woodland mice of the genus Peromyscus, especially P. leucopus, having white feet and undersides.
- white-spotted hyla — a type of tree frog (H. leucophyllata) of tropical America
- wild sweet william — blue phlox.
- wildlife sanctuary — an area where wild animals and plants are protected
- wind river systems — (company) A company founded in 1981, now a world leader in embedded systems, providing real-time operating systems and development tools. Wind River's development tools enable customers to standardise designs across projects and quickly develop feature-rich products. Wind River Systems employs over 500 people worldwide (1998). Service and support is provided through its U.S. headquarters and overseas operations in the U.K., France, Germany, Scandinavia and Japan. Address: Alameda, California, USA.
- winged everlasting — a bushy composite plant, Ammobium alatum, of Australia, having winged branches, javelin-shaped leaves, and white flowers.
- withdrawal symptom — effects of stopping a drug
- woe betide someone — misfortune will befall someone
- wood-burning stove — cooker: fueled by wood
- yeast nucleic acid — RNA.