system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If something is airtight is it also watertight? And vice versa?
gpt
Airtight will always be watertight, but watertight does not also mean airtight.  If something that is watertight is airtight, it will just be called airtight since that term encompasses both.

I always thought of balloons as an example.  If you tie a balloon off with some air in it,  it will deflate gradually over a few days.  However, you can try as much as you want to pour some water on it and see if any gets inside.  You won't have any luck.