18-letter words containing p, a, s, m, r, c
- upper middle class — wealthy, highly-educated people
- world championship — an international competition in a particular sport or activity for people all around the world
- x-ray spectrometer — a spectrometer using x-rays to activate the inner electrons of an atom in order to separate and identify the chemical constituents of a substance and their concentrations.
- x-ray spectrometry — the use of an x-ray spectrometer.