Meanwhile
Part of speech: adverb
Definition: During the time (that something is happening). At the same time, but elsewhere.
Part of speech: noun
Definition: The time between two events
Example sentence: Even though I'm often crazy - and I am, and I know it - still I fight it because I know how sterile, how futile, how bleak... nothing grows from it, and you, meanwhile, only grow into it like a snail.
Meantime
Part of speech: noun
Definition: The time spent waiting for another event; time in between.
Part of speech: adverb
Definition: during the interval; meanwhile
Example sentence: For countries such as Kenya to emerge as economic powerhouses, they need better infrastructure: roads, ports, smart grids and power plants. Infrastructure is expensive, and takes a long time to build. In the meantime, hackers are building 'grassroots infrastructure,' using the mobile-phone system to build solutions that are ready for market.