Al ‧ ex ‧ an ‧ dra Pal ‧ ace /ˌælɪɡzɑːndrə ˈpæləs $ -zæn-/ BrE AmE ( also Ally Pally informal )
a large building in North London that was built in 1873 and is now used for ↑ conference s (=large business or political meetings) and concerts. It also has a famous metal tower from which the first television signals were broadcast by the BBC.