trenches
ocean volcanos Sometimes they're called trenches. The Marianas Trench in the Pacific is the deepest point in all the world's oceans.
an abyss
A black hole doesn't have depth. Despite it being called a "hole", it is actually a spherical object that has a singularity at it's centre (where gravity and mass is infinite), and an event horizon that marks the point at which the force of gravity is so strong that not even light can escape. If, by "depth" you meant "diameter", the answer still isn't certain since the diameter of a black hole depends on it's mass (which can be almost anything).
The hole in a pencil sharpener is called the "shaving hole" or the "sharpening hole." This is where you insert the pencil to sharpen it.
a hole in your stomach is called an ulcer
It is called a blow hole.
Plankton...microscopic.
I knew a watering hole called Brian. His brother was called Jim
They are obtained by drilling a hole in the crust of the earth underneath the ocean.
A port hole ?
Because it's to have sex
There is no black hole in the Pacific Ocean. Black holes are astronomical phenomena that occur in outer space and cannot form within Earth's oceans.