Definition of "oxy"

oxy¹

noun
uncountable
1. (chemistry) The bivalent R-O-R functional group found in ethers.

oxy²

noun
countable and uncountable, plural oxies
1. (informal) Clipping of oxyacetylene, a mixture of oxygen and acetylene used for cutting and welding metals.
2. (countable, uncountable, slang, pharmacology) Clipping of oxycodone, an opioid similar to heroin.
  Quotations
  One of the detectives, Sgt. Joseph Ballou, discovered that during a drug raid in 2012, Springfield cops had confiscated 51 oxycodone pills — the gold standard of prescription opioids. ¶ The oxies were turned over to Farak for analysis and she issued a certificate saying the pills were not illegal.
  2017 July 2, Howie Carr, “Carr: Judge sees misconduct, AG sees none”, in Boston Herald‎
3. (informal) Clipping of oxygen.