Era

ERA

Abbreviation for electronic remittance advice.

effective radiating area

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ERA

The area of a therapeutic ultrasound head that produces useful ultrasonic energy, measured in square centimeters (cm²). The effective radiating area is calculated by identifying all points where the ultrasonic energy is at least 5% of the maximum measured intensity at the transducer's surface.

Era

a division of geological time, such as Cenozoic, Mesozoic, Palaeozoic, which is itself divided into periods. See GEOLOGICAL TIME.