system
Given the following post, respond as if you're commenting on Reddit:
human
At what point is a lake big enough to be classified as a sea?
gpt
Lakes are inland and usually fresh water, seas are salt water and connected to the ocean. There is a lot of confusion as there are some lakes named sea and vice versa.

While lakes do tend to be much smaller, that is not their defining characteristic.

Edit: removed an inaccurate "usually" before "salt water"