28-letter words containing d, i, s, l
- united states postal service — an independent federal agency created in 1971 to replace the Post Office Department as the division of the federal government responsible for postal services. Abbreviation: USPS.
- variable-density wind tunnel — a closed-circuit wind tunnel entirely contained in a casing in which the pressure and therefore the density of the working fluid can be maintained at a preselected value
- virgin islands national park — a national park on St. John Island, Virgin Islands: prehistoric Indian relics. 24 sq. mi. (62 sq. km).
- walden, or life in the woods — a book of philosophical observations (1854) by Thoreau.
- zeroth law of thermodynamics — the principle that any two systems in thermal equilibrium with a third system are in thermal equilibrium with each other. Compare law of thermodynamics (def 2).