A bolthole is a place you can escape to. A country bolthole, a useful bolthole, retreat to the bolthole.
It is often a second home in estate agents' language and a hiding place in everybody else's. The image is a rabbit's escape burrow, which is where the word begins.
1nounboltholeA place you can escape to.
“They bought a little cottage in Cornwall as a bolthole from the noise of London.”
bolthole is a refuge.
Bolt plus hole, from the escape burrow a rabbit bolts down.
From bolt + hole.
Etymology from Wiktionary, CC BY-SA
Practised in A Song of Ice and Fire