Abbreviation of 砲台場. Refers to a coastal defense fortification or gun battery, especially in historical contexts (e.g., Edo period).
The shogunate built coastal batteries off Shinagawa.
Odaiba is located on the site of a battery built in the Edo period.
この台場は外国船の侵入を防ぐために造られた。
This fort was built to prevent the intrusion of foreign ships.
Soldiers were stationed to defend the coastal battery.
要塞 is the broad term for any fortress or stronghold, whereas 台場 refers specifically to a coastal artillery battery, especially from the Edo period.
Abbreviation of 砲台場 (ほうだいば), literally 'cannon platform place'. The term became widely known through the Edo-period coastal defenses built in Tokyo Bay, now preserved in the place name お台場 (Odaiba).