17-letter words containing f, a, c, d, i
- traffic diversion — a special route arranged for traffic to follow when the normal route cannot be used
- 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.
- unclassified road — a road that has not been given a grade because it is of a basic standard
- wind chill factor — A wind chill factor is a measure of the cooling effect of the wind on the temperature of the air.
- wind-chill factor — the apparent temperature felt on the exposed human body owing to the combination of temperature and wind speed.
- with a difference — If you describe a job or holiday, for example, as a job with a difference or a holiday with a difference, you mean that the job or holiday is very interesting and unusual.
- x-ray diffraction — diffraction of x-rays by the regularly spaced atoms of a crystal, useful for determining the arrangement of the atoms.
- zone of avoidance — the area of the sky in the plane of the Milky Way where interstellar dust obscures visible light so that no distant galaxies can be observed.