bedboard

noun
UK /ˈbɛdbɔːd/
US /ˈbɛdbɔːrd/

A bedboard is the flat hard part under a bed's mattress that holds it up.

Dad slid the bedboard into the frame before we put the mattress on.


OTHER MEANINGS

2. A board placed at the head of a bed or against a wall to protect it.

They nailed a bedboard to the wall so the paint wouldn't get scuffed.

3. A flat board used as a simple bed or sleeping surface.

The hikers slept on wooden bedboards in the cabin.

4. A board forming part of a bed frame in furniture construction.

The carpenter replaced the cracked bedboard on the old oak bed.