18-letter words containing p, i, n, e, f
- torsion-free group — a group in which every element other than the identity has infinite order.
- unfair competition — acts done by a seller to confuse or deceive the public with intent to acquire a larger portion of the market, as by cutting prices below cost, misleading advertising, selling a spurious product under a false identity, etc.
- vermiform appendix — a narrow, blind tube protruding from the cecum, having no known useful function, in humans being 3 to 4 inches (8 to 10 cm) long and situated in the lower right-hand part of the abdomen.
- visiting professor — a professor from another institution invited to teach at a university or college for a limited period, usually for a semester or one academic year.
- wild passionflower — the maypop, Passiflora incarnata.