svećica

1. small candle
   Duni u svećice na torti i zamisli želju! — Blow out the candles on the cake and make a wish!
   Upalila je svećicu u crkvi za baku. — She lit a candle in church for her grandmother.
2. (in an engine) spark plug
   Majstor je rekao da treba promeniti svećice. — The mechanic said the spark plugs need replacing.

An ordinary candle is sveća; svećica is a small candle or a spark plug.