immersion [ǝ`mǝr·zhǝn] ASTRONOMY The disappearance of a celestial body either by passing behind another or passing into another's shadow. MATHEMATICS A mapping f of a topological space X into a topological space Y such that for every x ∊ X there exists a neighborhood N of x, such that f is a homeomorphism of N onto f (N ). SCIENCE AND TECHNOLOGY Placement into or within a fluid, usually water. |