This reference page explains commonly used abbreviations, acronyms, and symbols found in lubricant technical documentation, specifications, standards references, and product data sheets. Entries are descriptive and provided to support accurate interpretation of technical language.
Abbreviations and symbols are used to condense performance requirements, classification systems, and test references into standardised formats. Their meaning should always be interpreted within the context of the relevant standard, specification, or manufacturer documentation.
Common abbreviations and symbols
ISO VG
International Organisation for Standardisation viscosity grade system used to classify industrial lubricants based on kinematic viscosity at 40 °C.
SAE
Society of Automotive Engineers viscosity classification system primarily used for engine oils and automotive lubricants.
ACEA
European Automobile Manufacturers’ Association engine oil performance classifications used in European vehicle specifications.
API
American Petroleum Institute engine oil service categories defining minimum performance requirements for specific engine types.
DIN
Deutsches Institut für Normung standards referenced in industrial lubricant classifications, performance definitions, and test methods.
ASTM
American Society for Testing and Materials test methods used to define lubricant physical, chemical, and performance characteristics.
HLP
DIN hydraulic oil classification indicating the presence of anti wear additives, oxidation stability, and corrosion protection.
HVLP
DIN hydraulic oil classification for high viscosity index fluids designed to maintain viscosity stability across temperature ranges.
EP
Extreme pressure additive designation indicating chemistry intended to reduce wear under high load conditions.
TBN
Total Base Number, a measure of a lubricant’s alkaline reserve, primarily used in engine oil analysis.
TAN
Total Acid Number, indicating the level of acidic components present in a lubricant.
VI
Viscosity index, describing the rate at which a lubricant’s viscosity changes with temperature.
µ (mu)
Symbol representing the coefficient of friction in tribology and lubrication analysis.