say it: PER-uh-laks
parallax is a noun meaning "the apparent displacement of an object as seen from two different points that are not on a line with the object". It carries one recorded sense.
the apparent displacement of an object as seen from two different points that are not on a line with the object
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for parallax come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.