山砦[sansai] mountain stronghold
城砦[jousai] fortress
砦を落とす[toridewootosu] to capture a fort

砦を築く[toridewokizuku] to construct a fort
鹿砦[rokusai] abatis

改築[kaichiku] structural alteration of building
建築[kenchiku] construction
建築家[kenchikuka] architect
構築[kouchiku] construction
再建築[saikenchiku] reconstruction

再構築[saikouchiku] reconstruction
修築[shuuchiku] repair
上層建築[jousoukenchiku] superstructure
新築[shinchiku] new building
増築[zouchiku] addition to a building