In architecture:
* A transom is a horizontal crosspiece over a door or window. It can be decorative, providing extra support, or serve as a ventilation panel.
In marine design:
* A transom is the vertical, usually curved, stern of a boat. It provides structural support for the boat's hull and can be used for mounting an outboard motor.
In other contexts:
* A transom can also be a beam or lintel, often used in construction.
It's important to consider the context in which you're encountering the word "transom" to understand its meaning. If you can provide more context, I can give you a more specific answer.