What does "spark" mean?

Additional senses

1. 2.That which, like a spark, may be kindled into a flame, or into action; a feeble germ; an elementary principle. "If any spark of life be yet remaining." Shak. "Small intellectual spark." Macaulay. "Vital spark of heavenly flame." Pope. We have here and there a little clear light, some sparks of bright knowledge. Locke. Bright gem instinct with music, vocal spark. Wordsworth. Spark arrester, a contrivance to prevent the escape of sparks while it allows the passage of gas, -- chiefly used in the smokestack of a wood-burning locomotive. Called also spark consumer. [U.S.]
2. 3.A brisk, showy, gay man. The finest sparks and cleanest beaux. Prior.
3. 4.A lover; a gallant; a beau.
4. 5.To sparkle. [Obs.] Spenser.
5. 6.To play the spark, beau, or lover. A sure sign that his master was courting, or, as it is termed, sparking, within. W. Irwing.