What does "meantime" mean?

The time spent waiting for another event; time in between.

What is a synonym for "meantime"?

Common synonyms include: interim, at the same time, betweentimes, entre temps, eon, for the time being.

/ˈmiːntaɪm/ adv, noun

adv, noun ·Rare ·Advanced level

Noun

1
The time spent waiting for another event; time in between. countable, uncountable
"We'll come back asap; just wait here for the meantime."
2
the time between one event, process, or period and another wordnet

Adverb

1
During the interval; meanwhile. not-comparable
"Repairs will be done tomorrow so meantime restrain from using the bath."

Adverb

"In the meantime, she began to cry."

From Middle English menetime, equivalent to mean + time. Adverb is by ellipsis from in the meantime.