oxycodone also goes by the trade name OxyContin
OxyContin is a much higher dosage of oxycodone than Percocet, designed for time-release delivery. Because of the higher dosage's danger and value as a recreational drug, it's much more tightly regulated. For a legit Oxy script you've gotta be in some dire straits, which is why my Percocet guess was far more likely (even though it was wrong). Still, enjoy the high.