Asynchronous means not happening at the same time, especially when people or systems do not need to be active together to communicate or work.
It comes from Greek *a-* 'not' and *synchronos* 'happening at the same time', from *syn-* 'together' and *chronos* 'time'. So it literally means 'not in the same time'.
Email, online courses, and many apps are asynchronous: they let people cooperate without matching schedules. Once you notice this, you see a hidden superpower of modern life—we can now work together even while living in totally different time zones and rhythms.
Complete word intelligence in one call. Free tier — 50 lookups/day.