17-letter words containing d, i, p, f
- springfield rifle — a single-shot, breechloading .45-caliber rifle used by the U.S. Army from 1867 to 1893.
- stratified sample — a sample that is not drawn at random from the whole population, but separately from a number of disjoint strata of the population in order to ensure a more representative sample
- striped killifish — a killifish, Fundulus majalis, of the Atlantic coast of the U.S., the female of which is marked with black stripes.
- to play the field — If someone plays the field, they have a number of different romantic or sexual relationships.
- trapdoor function — a function defined from data by means of a mathematical procedure in such a way that it is easy to obtain the function when the data are known, but when the procedure and data are not known it becomes very difficult to determine the original data: used in cryptography, where the data are the characters of the plain text, or message, and the trapdoor function is the cryptogram.