Praetorium

The Greek word (praitorion) thus rendered in Mark 15:16 is
rendered "common hall" (Matt. 27:27, marg., "governor's house"),
"judgment hall," (John 18:28, 33, marg., "Pilate's house", 19:9;
Acts 23:35), "palace" (Phil. 1:13). This is properly a military
word. It denotes (1) the general's tent or headquarters; (2) the
governor's residence, as in Acts 23:35 (R.V., "palace"); and (3)
the praetorian guard (See PALACE T0002827), or the camp or
quarters of the praetorian cohorts (Acts 28:16), the imperial
guards in immediate attendance on the emperor, who was "praetor"
or commander-in-chief.