In general usage, an essential part of a thing surrounded by other essential things. • The central part of a fruit, containing the kernels or seeds. • The heart or inner part of a physical thing. • The anatomical core, muscles which bridge abdomen and thorax. • The center or inner part of a space or area. • The most important part of a thing or aggregate of things wherever located and whether of any determinate location at all; the essence. • A technical term for classification of things denoting those parts of a category that are most easily or most likely understood as within it. • The main and most diverse monophyletic group within a clade or taxonomic group. • The set of feasible allocations that cannot be improved upon by a subset (a coalition) of the economy's agents. • A thematic aesthetic; objects related to a specific topic • particular parts of technical instruments or machines essential in function: • The portion of a mold that creates a cavity or impression within the part (casting or molded part) or that makes a hole in or through the part. • Ellipsis of core memory (“magnetic data storage”). • An individual computer processor, in the sense when several processors (called cores or CPU cores) are plugged together in one single integrated circuit to work as one (called a multi-core processor). • The material between surface materials in a structured composite sandwich material. • The inner part of a nuclear reactor, in which the nuclear reaction takes place. • The central fissile portion of a fission weapon. • A piece of ferromagnetic material (e.g., soft iron), inside the windings of an electromagnet, that channels the magnetic field. • A hollow cylindrical piece of cardboard around which a web of paper or plastic is wound. • Hence particular parts of a subject studied or examined by technical operations, likened by position and practical or structural robustness to kernels, cores in the general sense above. • A tiny sample of organic material obtained by means of a fine-needle biopsy. • The bony process which forms the central axis of the horns in many animals. • A disorder of sheep caused by worms in the liver. • The central part of a protein's structure, consisting mostly of hydrophobic amino acids. • A cylindrical sample of rock or other materials obtained by core drilling. • An atomic nucleus plus inner electrons (i.e., an atom, except for its valence electrons).