Wishing you and your family a Merry Christmas!

What is the original name of the engineering element on our Christmas card?

The original name is a cogwheel.
A cogwheel is a toothed wheel that is designed to transmit the torque
to another adjacent cogwheel. Some historians believe the
cogwheel dates back to at least the 4th century B.C.

Today, we call these things GEARS.