Doppler ultrasound is a type of ultrasound that depends on the Doppler Effect, a change in the wave's frequency, which can occur from the motion of a reflector, such a red blood cell. We experience the Doppler Effect when, for example, an ambulance approaches us, passes and then drives away.
Definition of PLACODERM. : any of a class (Placodermi) of extinct chiefly Devonian fishes with an armor of bony plates and primitive jaw structures.ADVERTISEMENT. New Latin Placodermi, ultimately from GK plak-, plax + derma skin â more at derm-. any of a class (Placodermi) of extinct chiefly Devonian fishes with an armor of bony plates and primitive jaw structures. ADVERTISEMENT.
Origin of PLACODERMI. New Latin, from plac- + Greek derma skin â more at derm-. This word doesn't usually appear in our free dictionary, but the definition from our premium Unabridged Dictionary is offered here on a limited basis.Note that some information is displayed differently in the Unabridged.rigin of PLACODERMI. New Latin, from plac- + Greek derma skin â more at derm-. This word doesn't usually appear in our free dictionary, but the definition from our premium Unabridged Dictionary is offered here on a limited basis. Note that some information is displayed differently in the Unabridged.