|inztən|tānēəs, |in(t)stə-, -ānyəs adjective
Etymology: Medieval Latin instantaneus, from Latin instant-, instans (present participle) + -aneus (as in subterraneus subterranean)
1. : done, occurring, or acting without any perceptible duration of time
instantaneous death
instantaneous heaters
2.
a. : done without any delay being introduced purposely
instantaneous action
b. of a sound recording : capable of being used as soon as recorded
3. : occurring or present at a particular instant
instantaneous value
instantaneous velocity
instantaneous voltage
• in·stan·ta·ne·ous·ly adverb
• in·stan·ta·ne·ous·ness noun -es