The Greek eiseimi means to go in or enter. It appears in Acts 3:3 when the lame man sees Peter and John 'about to enter (eisienai) the temple' and asks for alms. In Acts 21:18, Paul goes in (eisēei) to James with the elders. In Hebrews 9:6, 'the priests always entered (eisiasin) the outer room to carry on their ministry.'
The eiseimi of the priests entering the sanctuary (Hebrews 9:6) is contrasted with the once-yearly entrance of the high priest into the Holy of Holies. This ritual geography — the separation of courts, the limited access, the daily service versus the annual approach — was a physical sermon: 'the Holy Spirit was showing by this that the way into the Most Holy Place had not yet been disclosed' (Hebrews 9:8). Christ's once-for-all entry (Hebrews 9:12) through his own blood opened what no Levitical priest could open. Believers now eiseimi freely into the presence of God (Hebrews 10:19-22).