18-letter words containing o, p, e, n, s
- wild passionflower — the maypop, Passiflora incarnata.
- wilson's phalarope — a phalarope, Phalaropus tricolor, that breeds in the prairie regions of North America and winters in Argentina and Chile.
- wireless telephone — Now Rare. radiotelephony.
- wireless telephony — Now Rare. radiotelephony.
- women at point sur — a narrative poem (1927) by Robinson Jeffers.
- working hypothesis — See under hypothesis (def 1).