Wiktionary
alt. A small candle which burns from a wick immersed in molten wax. n. A small candle which burns from a wick immersed in molten wax.
Wikipedia
A tealight (also tea-light, tea lites or tea light, t-lite or tcandles), or nightlight, is a candle encased in a thin metal or plastic cup so that the candle can liquefy completely while lit. They are typically small, circular, wider than their height and inexpensive. Because of their small size and low level of light, multiple tealights are often burned simultaneously.
Tealights derive their name from their use in teapot warmers, but are also used as food warmers in general, e.g. fondue. They are a popular choice for votive candles. They are also suitable for accent lighting and for heating scented oil. Tealights may be floated in water for decorative effect.
Tealights may be distinguished from nightlights by the candle size; A tealight usually burns for 3 to 5 hours, but a nightlight (any candle you wish to use as a "nightlight") burns for as long as the manufacturer claims it will.