kernel

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A grain or seed, as of a cereal grass, enclosed in a husk.
2. n. The inner, usually edible seed of a nut or fruit stone.
3. n. The most material and central part; the core: "that hard kernel of gaiety that never breaks” ( Evelyn Waugh).

Century Dictionary and Cyclopedia

1. n. The edible substance contained in the shell of a nut or the stone of a fruit.
2. n. Technically, in botany: In phanerogams, strictly, the whole body of a seed within the coats, namely, the embryo, and, when present, the albumen.
3. n. In pyrenomycetous fungi, in old usage, all of the soft parts of the pyrenocarp or perithecium within the firm outer wall. In both these senses a synonym of nucleus.
4. n. A gramineous seed with its husk or integument; a grain or corn: as, a kernel of wheat, oats, or maize: formerly applied also to the seed of the apple and other pulpy fruits.
5. n. The bundle of fat on the fore shoulder; any swelling or knob of flesh.
6. n. Figuratively — The central part of anything; a mass around which other matter is concreted; a nucleus in general.
7. n. The important part of anything, as a matter in discussion; the main or essential point, as opposed to matters of less import; the core; the gist: as, to come to the kernel of the question.
8. To harden or ripen into kernels, as the seeds of plants.
9. n. A battlement.
10. To crenelate.
11. n. An enlarged lymphatic gland.
12. n. In metallurgy, a nucleus of a double sulphid of copper and iron obtained in roasting cupriferous iron pyrites. The kernels are separated by hand from the lumps of pyrites and are melted for copper.

Wiktionary

1. n. The core, center, or essence of an object or system.
2. n. The central (usually edible) part of a nut, especially once the hard shell has been removed.
3. n. A single seed or grain, especially of corn or wheat.
4. n. US The stone of certain fruits, such as peaches or plums.
5. n. computing The central part of many computer operating systems which manages the system's resources and the communication between hardware and software components.
6. n. mathematics, algebra Those elements, in the domain of a function, which the function maps to zero.
7. n. mathematics The set of members of a fuzzy set that are fully included (i.e., whose grade of membership is 1).

GNU Webster's 1913

1. n. The essential part of a seed; all that is within the seed walls; the edible substance contained in the shell of a nut; hence, anything included in a shell, husk, or integument. See Illust. of endocarp.
2. n. A single seed or grain.
3. n. A small mass around which other matter is concreted; a nucleus; a concretion or hard lump in the flesh.
4. n. The central, substantial or essential part of anything; the gist; the core.
5. v. To harden or ripen into kernels; to produce kernels.

WordNet 3.0

1. n. the choicest or most essential or most vital part of some idea or experience
2. n. a single whole grain of a cereal
3. n. the inner and usually edible part of a seed or grain or nut or fruit stone