both refer to movie chains (i.e., Loews, AMC Theatres) with movie theatres that screen more than one film at a time, as opposed to single-screen theatres. A multiplex has from 2 up to 16 screens, a megaplex has 16 or more screens; plex is the abbreviation for a multiplex theatre.
A morula (Latin, morus: mulberry) is an early stage embryo consisting of cells (called blastomeres) in a solid ball contained within the zona pellucida.
macula - a small yellowish central area of the retina that is rich in cones and that mediates clear detailed vision. macula lutea, macular area, yellow spot. region, area - a part of an animal that has a special function or is supplied by a given artery or nerve; in the abdominal region. retina - the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve.