- The definition of instantaneous is something that happens right away.
If you ask for water and water immediately appears that very second, this is an example of something instantaneous.
- done, made, or happening in an instant
- done or made without delay; immediate: an instantaneous reply
- existing at a particular instant
Origin of instantaneousMedieval Latin instantaneus
- Occurring or completed without perceptible delay: Relief was instantaneous.
- Done or made as quickly or directly as possible: an instantaneous reply to my letter.
- Present or occurring at a specific instant: instantaneous velocity; instantaneous pressure.
Origin of instantaneousFrom Medieval Latin īnstantāneus, from Latin īnstāns, īnstant-, present; see instant.
New Latin, 17th century