I often forget that not everyone speaks plumbing. To make things more complicated some plumbing component names are not self-explanatory at all.
If you have to buy a part, look something up, or call a plumber it will be easier if you know the names of the plumbing components.
The bathroom sink, for example, has quite a few plumbing parts that can break, leak, or become blocked.
So, let's take a look at what is under the bathroom sink.