[ ˌɪnst(ə)n'teɪnɪəs ]
■ adjective
1》 occurring or done instantly.
2》 Physics existing or measured at a particular instant.
Derivatives
instantaneity noun
~ly adverb
~ness noun
Origin
C17: from med. L. instantaneus , from L. instant- (from instare 'be at hand').