18-letter words containing a, p, o, s, t, e
- white-spotted hyla — a type of tree frog (H. leucophyllata) of tropical America
- women at point sur — a narrative poem (1927) by Robinson Jeffers.
- 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.