n. a deep, narrow, long hole
They had to dig trenches in the ground.

n. a ship that can travel under the sea
Submarines are boats that move under water.

n. relating to things below the surface of the sea
The Mariana Trench is a deep, long, narrow undersea valley along the seafloor in the western Pacific Ocean.

n. very cold, especially below 0°C when water becomes ice
It was freezing cold last night; I had to use 5 blankets.

n. the amount of physical force pushing on something
They put pressure on him to change his mind.

n. the person who controls how a movie is made
This movie involved a famous director.

n. a space where the sides are close together; opposite of 'wide'
Only one car could fit on the narrow road.

n. the low area of land between hills or mountains
There is a beautiful river in the middle of the valley.

n. the smallest working part of a living thing
All living things are made up of cells.

n. the bottom of the ocean or sea
The seafloor has many interesting sites that have never been seen before.