A Greek noun meaning tongue (the physical organ), language, speech. It refers both to the bodily tongue and to spoken language. In the New Testament, it gains special theological significance through the phenomenon of 'speaking in tongues' (lalein glōssais) — the supernatural gift of speaking in unlearned languages or ecstatic speech.
The theology of glōssa spans from creation to consummation. James warns that the tongue is 'a restless evil, full of deadly poison' (James 3:8) — small but destructive when uncontrolled. Yet at Pentecost (Acts 2:4), the Spirit empowers the disciples to speak in other tongues — the curse of Babel is reversed as every nation hears the gospel in their own language. Paul addresses the Corinthian controversy by regulating tongues-speech: it must be interpreted, it must build up the church, and love matters more than any gift (1 Corinthians 14). Revelation 7:9 depicts every 'tongue' confessing before the throne. The trajectory: human tongues are dangerous when self-directed, powerful when Spirit-directed, and ultimate when Christ-directed (Philippians 2:11: 'every tongue confess that Jesus Christ is Lord').