- erythrocyte sedimentation rate, ESR, sedimentation rate, sed rate - the rate at which red blood cells settle out in a tube of blood under standardized conditions; a high rate usually indicates the presence of inflammation
--1 is a kind of rate
- electron spin resonance, ESR, electron paramagnetic resonance - microwave spectroscopy in which there is resonant absorption of radiation by a paramagnet
--2 is a kind of microwave spectroscopy