HCY

HCY may refer to:

• Homocysteine, an amino acid
• {{lang|fr|Hôpital Central de Yaoundé|italics=no}}, a Cameroonian hospital
• Tsuen Wan Public Ho Chuen Yiu Memorial College, a Hong Kong secondary school
• Helios Airways, a Cypriot airline (1998–2006; ICAO:HCY)

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