A portable lamp, typically an oil lamp — the primary source of indoor illumination in the ancient world. Used metaphorically for spiritual illumination, divine guidance, and the believer's witness.
The lychnos is one of Jesus' favorite metaphors. 'No one lights a lamp and puts it under a basket' (Matt 5:15) — your life is meant to shine. 'The eye is the lamp of the body' (Matt 6:22) — what you focus on determines whether your inner world is light or dark. John the Baptist was 'a burning and shining lamp' (John 5:35). In Revelation 21:23, the Lamb IS the lamp of the New Jerusalem — all earthly lamps were pointing to Him.