What is the piece on the back of the television called that u connect the cable wire to?

Because mine came off and for some reason is impossbile screw back on even though it look like it can be easily screwed in. I have a Orion older model black tube television about 27 inches. I need to know so i can either order the part or... look up how to fix it. Im doomed!

This part is known as a coaxial female jack [for antenna in]

coaxial - Good Luck repairing it, I got no clue how

The antenna in connectors are "Type F" connectors. If you are referring to the connector on the back of the set it is a Type F Female connector.

If you are referring to the end of the cable, that is a Type F Male connector. They are readily available at Radio Shack or even Lowes & Home Depot along with the crimp tool to install them. You can put a new connector on a cable yourself, it's an easy repair.