The word pound can have several meanings.
It could mean to hit something hard, many times, for example "he pounded the meat to tenderize it".
It could mean a unit of British money, equaling 100 pence.
It might also mean a unit of weight, abbreviated to lb, equalling 0.453kg, or 0.373kg for precious metals. The picture is of a pound of flour.
Sound is something that you hear through your ears. It is made up of vibrations that can travel through air as well as many other substances. Sound won't travel through everything - many substances block sound.
Uis forUltrasound
An ultrasound is a medical scan that uses soundwaves to "see" what is happening inside you. Ultrasounds are most often used to look at unborn babies while they are developing.