Open English Wordnet
Nouns
(n)central, telephone exchange, exchangea workplace that serves as a telecommunications facility where lines from telephones can be connected together to permit communication Adjectives
(s)cardinal, central, fundamental, key, primalserving as an essential component“a cardinal rule”,
“the central cause of the problem”,
“an example that was fundamental to the argument”,
“computers are fundamental to modern industrial structure” (a)centralin or near a center or constituting a center; the inner area“a central position”