16-letter words containing a, t, p, u, l
- upsilon particle — the 20th letter of the Greek alphabet (Υ, υ).
- ventriculography — radiography of the ventricles of the heart after injection of a contrast medium
- virtual particle — an elementary particle of transitory existence that does not appear as a free particle in a particular situation but that can transmit a force from one particle to another.
- voluntary helper — a person who aids or assists in a specified function of one's own accord and without compulsion or promise of remuneration
- water lily tulip — a showy tulip, Tulipa kaufmanniana, of Turkestan, having spreading, white or pale-yellow flowers with yellow centers streaked with red.