What does it mean?

GDPRGeneral Data Protection Regulation
DPOData Protection Officer
SAR or DSARSubject Access Request / Data Subject Access Request
PIAPrivacy Impact Assessment 
Data Protection Act (Being replaced by GDPR in May 2018)
Data Protection Authority (For the UK this is the ICO and is different for other EU countries)
DPDData Protection by Design

DPIAData Protection Impact Asssessment
ICOInformation Commissioner's Office
PCI DSSPayment Card Industry Data Security Standard