18-letter words containing a, b, n, d
- to be on the radar — to be noticed or important
- transporter bridge — a bridge for carrying passengers and vehicles by means of a platform suspended from a trolley.
- trobriand islander — a native or inhabitant of the Trobriand Islands of Papua New Guinea
- under one's breath — the air inhaled and exhaled in respiration.
- under the jackboot — If a country or group of people is under the jackboot, they are suffering because the government is cruel and undemocratic.
- united arab states — a former (1958–61) federation of the United Arab Republic (Egypt and Syria) and Yemen.
- universal debugger — (tool, parallel) (udb) KSR's interactive source level debugger for serial and parallel programs written in KSR, Fortran, KSR C and KSR1 assembly language. Udb is a source level debugger for testing and debugging serial and parallel programs; it is compatible with GDB and dbx. The user can direct udb either by typing commands or graphically through an X-based window interface; the latter provides simultaneous display of source code, I/O and instructions. For parallel programs, operations can be carried out per-thread.
- urban homesteading — homesteading (def 2).
- wardrobe assistant — a person who assists the wardrobe mistress in a theatre
- white man's burden — the alleged duty of white colonizers to care for nonwhite indigenous subjects in their colonial possessions.
- widemouth blindcat — any of several catfishes, as Satan eurystomus (widemouth blindcat) of Texas, that inhabit underground streams and have undeveloped eyes and unpigmented skin.