The time between two events.
"While I was finishing my homework, meanwhile, my brother played video games in his room."
In plain English: Meanwhile is not actually used as a noun, so it has no meaning when treated that way; instead, people use it to mean something happening at the same time as another event.
"While I finished my homework, meanwhile was when my brother started playing video games in another room."
Usage: Use this word as an adverb to describe actions occurring at the same time, not as a noun referring to a specific duration. Avoid treating it like "meanwhile" in phrases such as "in meanwhile," which should instead be phrased with prepositions like "during that time."
during the intervening time
"meanwhile I will not think about the problem"
"meantime he was attentive to his other interests"
"in the meantime the police were notified"
During the time that something is happening.
"Meanwhile, while the chef prepared the dessert, the guests enjoyed appetizers in the garden."
In plain English: Meanwhile means at the same time that something else is happening.
"While I was fixing dinner, meanwhile my brother started setting the table."
Meanwhile comes from Middle English menewhile, which combined "mean" (meaning intermediate) with "while." The modern adverb evolved through a shortened form of the phrase "in the mean while," eventually becoming a single word in usage.