oasis

asylum, bolt-hole [chiefly British], harbor, harborage, haven, refuge, retreat, sanctuary, sanctum, shelter

anchorage, mooring, port

cover, screen

abode, diggings, domicile, dwelling, habitation, house, housing, lodging, lodgment (or lodgement), pad, place, quarters, residence, rest, roof

cloister, closet, covert, den, hermitage, hideaway, hideout, lair

castle, fastness, fort, fortress, palisade, redoubt, stronghold

lean-to, lee, shed, windbreak