(set theory) The paradox that supposing the existence of a set of all ordinal numbers leads to a contradiction; construed as meaning that it is not a properly defined set.

(set theory) The paradox that a set defined to contain all sets which do not contain themselves can neither consistently contain itself nor not contain itself.

The seeds or seed capsules of Aframomum melegueta, used as a medicine and spice, especially as a substitute for black pepper and in flavoring alcoholic beverages.

plural of parallel universe

(sciences, science fiction) A universe that exists separately alongside another universe, as part of a multiverse.

The ring-necked parakeet (Psittacula krameri).

A species of parakeet, Psittacula krameri, prevalent in Asia and famous for escaping domestication and establishing wild populations in Britain.

Alternative letter-case form of Fermi paradox

(biology, exobiology) The seeming contradiction, serving as a challenge to believers in the existence of advanced lifeforms throughout the universe, that there is no scientific evidence that extraterrestrial civilizations have tried to visit or communicate with Earth.

The observation that the association of two variables for one subset of a population may be similar to the association of those variables in another subset, but different from the association of the variables in the total population.