In order to provide income over the lifetime of the retiree, the TDF is designed to increasingly invest in deferred annuities as the TDF reaches its target retirement date and investors in the TDF get older.
Freebase(0.00 / 0 votes)Rate this definition: Echocardiography. Echocardiogram, often referred to cardiac echo or simply an echo is a sonogram of the heart. Echocardiography uses standard two-dimensional, three-dimensional, and Doppler ultrasound to create images of the heart.
Definition. 1  Echocardiography is a diagnostic test that uses ultrasound waves to create an image of the heart muscle. Ultrasound waves that rebound or echo off the heart can show the size, shape, and movement of the heart's valves and chambers as well as the flow of blood through the heart.