Final answer:
In Act 5, Scene 5 of Macbeth, when Macbeth says "Out, out, brief candle!", the word 'candle' refers to life.
Step-by-step explanation:
In Act 5, Scene 5 of Macbeth, when Macbeth says, "Out, out, brief candle!", the word 'candle' refers to life. Macbeth uses the metaphor of a candle to describe life's brevity and fleeting nature. Just as a candle burns out quickly, life is short and soon comes to an end. This line conveys Macbeth's realization that life is transient and that death is inevitable.