A dropped ceiling is a type of ceiling that is lower than the original ceiling in a room. It is kind of like a big puzzle that you put together and hang up underneath the real ceiling.
First, you need a frame for the dropped ceiling. This is like a big square or rectangle made out of metal pieces that fit together like a puzzle.
Then, you put some special tiles on top of the frame. These tiles can be made out of all different materials like metal, plastic, or even wood.
The tiles sit on top of the frame and create a new ceiling that is lower than the original one. This can be really useful if you need to hide things like wires or pipes that are up above the original ceiling.
To make it look nice, sometimes people will paint the tiles or even put pictures on them. And that's basically what a dropped ceiling is!