What does "board up" mean?

To block doors or windows with boards, either to prevent access or as protection from storms, etc.

What is a synonym for "board up"?

Common synonyms include: board up windows, boarded.

verb

verb ·Rare ·Advanced level

Verb

1
To block doors or windows with boards, either to prevent access or as protection from storms, etc. transitive
"The metals from Upnor to the boarded-up Tankfield signal box (by a gateless level crossing) were very rarely used."
2
cover with wooden boards wordnet

"The metals from Upnor to the boarded-up Tankfield signal box (by a gateless level crossing) were very rarely used."