noun

• One who scalps, or removes the scalp of another.
• (US, Canada) One who scalps tickets to popular entertainment events: buying them in advance and then selling them (e.g. online or just outside the venue of the event), often at inflated prices.
• (by extension) One who scalps any other item with limited availability.
• (gambling) A gambler who scalps.
• (finance) A person on an open outcry exchange trading floor who buys and sells rapidly for his or her own account, aiming to buy from a seller and a little later sell to a buyer, making a small profit from the difference (roughly the amount of the bid/offer spread, or less).
• A machine for removing the ends of grain, such as wheat or rye, or for separating the different grades of broken wheat, semolina, etc.
• A surgical instrument for scraping carious bones.