Definition from Wiktionary, the free dictionary
sideburn (plural sideburns)
- A style of facial hair with hair growing next to the ear down to the bend in the jaw.
- That guy grew his sideburns out long.
- His left sideburn was longer than the other one.
- (UK, smoking, uncountable) The unwanted rapid burning down one side of a cigarette that has been ineptly rolled.