"Lights" are candles or lamps used as a sign of festivity and solemnity in Christian worship. Altar lights are typically candles on an altar. See Candles in Worship. See Candles.
Glossary definitions provided courtesy of Church Publishing Incorporated, New York, NY,(All Rights reserved) from "An Episcopal Dictionary of the Church, A User Friendly Reference for Episcopalians," Don S. Armentrout and Robert Boak Slocum, editors.