17-letter words containing c, o, f, i, n, r
- x-ray diffraction — diffraction of x-rays by the regularly spaced atoms of a crystal, useful for determining the arrangement of the atoms.
- year of confusion — (in ancient Rome) the year of 445 days preceding the introduction, in 46 b.c., of the Julian calendar: lengthened to compensate for the cumulative errors of the Roman calendar.