21-letter words containing r, a, g, p, i
- spark ignition engine — A spark ignition engine is an engine running on the Otto cycle.
- spin angular momentum — to make (yarn) by drawing out, twisting, and winding fibers: Pioneer women spun yarn on spinning wheels.
- split-finger fastball — a type of fastball that sinks abruptly as it nears home plate, thrown with the grip used for a forkball
- supergranulation cell — one of a number of large convection cells in the photosphere and chromosphere of the sun, each having a diameter of 10,000–20,000 miles (16,000–32,000 km) and lasting longer than a day.
- tape operating system — (operating system) (TOS) An IBM operating system for System 360, used in the early days around 1965 to support the IBM 360 model 30 et al. TOS was a predecessor to IBM's Disk Operating System. TOS died out really early as disks such as the 2311 and 2314 became common with the IBM 360 whereas thet had been a real luxury on the IBM 7090.
- the acting profession — actors considered as a group
- the shipping forecast — a radio broadcast made by the BBC of weather reports and forecasts for the seas around the British Isles
- threshold wage policy — a policy whereby wages are increased in accordance with inflation
- topological invariant — a property of a topological space that is a property of every space related to the given space by a homeomorphism.
- transport segregation — Transport segregation is when particles from a mixture separate because the mixture vibrates while it is being moved.
- traveling salesperson — a representative of a business firm who travels in an assigned territory soliciting orders for a company's services.
- what price something? — what are the chances of something happening now?
- whip-and-tongue graft — a graft prepared by cutting both the scion and the stock in a sloping direction and inserting a tongue in the scion into a slit in the stock.
- wildlife photographer — someone that specializes in taking photographs of wild animals, especially in their natural habitats, and plants
- xeroderma pigmentosum — a rare inherited disease characterized by sensitivity to ultraviolet light, exposure resulting in lesions and tumors of the skin and eyes.