core-n; 6 Senses

Sense Number 1: the center region of an object

Commentary: CORE[+location][+region][+center]

The man threw an apple core out his car window.
The core of the earth is composed largely of nickel and iron.
The core of the induction coil was made of soft iron.
We got soaked to the core when a large wave broke over our bow.
The dentist packed the core of the tooth with a composite.
He is honest to the core. (idiomatic extension: he's good right down to the center)

WordNet 3.0 Sense Numbers: 2, 3

Sense Number 2: the key members of a social group or institution

Commentary: CORE[+structure][+social][+group][+members][+key][+organization/+institution/+team]
NOTE: refers to people

They have a core of experts looking into the problem.
That candidate may not be able to count on his core constituency this election.
He is believed to be affiliated with the core of a major terrorist organization.
The most conservative Republican core will not support this policy.

WordNet 3.0 Sense Numbers: 1

Sense Number 3: the essential or primary feature of something

Commentary: CORE[+quality][+essence]

The core of her belief could be described as rational empiricism.
During the meeting, he got right to the core of the issue.
Pete and John are hard core rock climbers.
The core curriculum for pre-med includes a lot of biochemistry and physics.
The company is focusing on its core competencies.

WordNet 3.0 Sense Numbers: 4, 7

Sense Number 4: a cylindrically-shaped specimen or sample, usually geological

Commentary: CORE[+entity][+structure][+physical][+sample][+cylindrical][+geological/+tissue]

Ice cores extracted from the arctic only go back as far as 300,000 years.
Paleontologists found interesting bone fragments in cores taken from the lake bottom.
The doctor removed a tiny core of tissue from the patient's breast and sent it to pathology.

WordNet 3.0 Sense Numbers: 5

Sense Number 5: the central chamber of a nuclear reactor

Commentary: CORE[+artifact][+chamber][+inner][+reactor][+nuclear]

This type of reactor will shut down if the core becomes too hot.
Workers removed spent uranium rods from the reactor's core.

WordNet 3.0 Sense Numbers: 6

Sense Number 6: a tiny ring of magnetic material used in computer memory

Commentary: CORE[+artifact][+ring][+magnetic][+small][+computer][+memory]

He was the original inventor of the small doughnut-shaped magnetic cores used in computer memories.
Early computers used small magnetic rings for their core memory.
John's C program did a core dump. (extension from the original meaning)

WordNet 3.0 Sense Numbers: 10