noun
watchtower; lookout tower
A raised structure used for observation, surveillance, or guarding, such as a fire lookout or prison watchtower.
森林火災を早期に発見するため、見張り台が設置された。
A watchtower was set up to detect forest fires early.
刑務所の見張り台からは敷地全体が見渡せる。
From the prison watchtower, you can see the entire grounds.
Compound of 見張り (みはり, 'watch, lookout') and 台 (だい, 'platform, stand').