PARALLAX is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek word parallaxis, meaning “alteration.” Due to foreshortening, nearby objects have a larger parallax than more distant objects when observed from different positions, therefore parallax can be used to determine distances.

PARALLEL lines are lines in a plane which do not meet; that is, two lines in a plane that do not intersect or touch each other at any point are said to be parallel. By extension, a line and a plane, or two planes, in three-dimensional Euclidean space that do not share a point are said to be parallel. However, two lines in three-dimensional space which do not meet must be in a common plane to be considered parallel; otherwise they are called skew lines. Parallel planes are planes in the same three-dimensional space that never meet.

PARADIGM is known as a type of proof. The purpose of paradigm is to provide an audience with an illustration of similar occurrences. This illustration is not meant to take the audience to a conclusion, however it is used to help guide them there. Anaximenes defined paradigm as "actions that have occurred previously and are similar to, or the opposite of, those which we are now discussing."

PARANORMAL phenomena include extrasensory perception (ESP), telekinesis, ghosts, poltergeists, life after death, reincarnation, faith healing, human auras, and so forth. The explanations for these allied phenomena are phrased in vague terms of "psychic forces", "human energy fields", and so on. This is in contrast to many pseudoscientific explanations for other nonparanormal phenomena, which, although very bad science, are still couched in acceptable scientific terms.