You wake up in the morning and say, "I wish I had a Samsung Galaxy S5". Async: you tell your personal assistant to go get you one. You continue your day, eat b

You wake up in the morning and say, "I wish I had a Samsung Galaxy S5". Async: you tell your personal assistant to go get you one. You continue your day, eat breakfast, build a shrine to hold your new phone and he comes back and says "they were out, I'm sorry, do you want me to go back and get an iPhone instead?" Non-Blocking: you try to click the buy it now on Amazon and it says, "Out of stock. Would you like to order and have fulfilled when back in stock?" you click yes. You eat breakfast, write the next Flappy Bird, and get actual work done. 4 days later it comes back in stock and your new phone arrives. If you missed the difference, Async, is "fire and check back later". Non-blocking is "error instantly, Perform later or in parallel". There are other differences but this is an easy analogy, that shows how the two are not synonyms.