ESR

ESR may refer to:

Technology:

• Electro Slag Remelting
• Electronic Staff Record, a human resources and payroll system of the UK National Health Service
• Emergency Sun Reacquisition, an attitude control mode of the Solar and Heliospheric Observatory (SOHO)
• Equivalent series resistance, the resistive parts of the impedance of certain electrical components
• ESR Technology, a UK company
• Emergency speed restriction or slow zone on British railways
• Extended Support Release, a line of Firefox developed separately, in order to maintain security.

Science:

• Electron spin resonance or electron paramagnetic resonance, a technique used in chemical spectroscopy to identify unpaired electrons and free radicals
• Erythrocyte sedimentation rate, a medical test for inflammation
• Estrogen receptor
• European Society of Radiology
• Environmental stress cracking, a cause of unexpected brittle failure of thermoplastic polymers
• EISCAT Svalbard Radar

Business:

• Environmental and Social Responsibility

Other:

• Experiment In Self-Reliance, a homelessness organization in Winston-Salem, NC
• East Somerset Railway, a heritage railway in the United Kingdom
• Institute of Environmental Science and Research, a New Zealand scientific institute
• Earlham School of Religion at Earlham College in Richmond, Indiana, United States
• Eric S. Raymond, an open source software advocate
• E.S.R., Inc.
• ESR, the IATA code for the Ricardo García Posada Airport