IPA: /ˌɪn.stənˈteɪ.ni.əs.li/
KK: /ˌɪnstəntəˈneɪəsli/
In a way that happens immediately and without any delay.
The system responds instantaneously to user commands.
Instantaneously → It is formed from "instant" (from Latin "instans", meaning immediate or present) and the suffix "-aneous" (meaning pertaining to or characterized by). The word "instantaneously" means occurring or done immediately, without any delay.
Think of something happening 'immediately' ('instant') and being 'characterized by' that immediacy ('-aneous'). This helps you remember that 'instantaneously' refers to something that occurs right away.