HCA?
I believe it's "lub" and "dup". (p. 493, under "heart sounds" heading...second sentence)
Lubb dubb corresponds to the heart sounds heard during systole and diastole, respectively.
lub dub
Lub dub
Phonocardiogram
Phonocardiogram. It is a visual representation of the sounds produced by the heart during the cardiac cycle, including the closure of heart valves. By analyzing the phonocardiogram, healthcare professionals can assess the timing and characteristics of heart sounds to help diagnose heart conditions.
Heart sounds originate from the closure of heart valves during the cardiac cycle. The first heart sound (S1) is produced by the closure of the mitral and tricuspid valves, while the second heart sound (S2) is caused by the closure of the aortic and pulmonary valves. These sounds can be heard using a stethoscope during a physical examination.
Onomatopoeia
The word is spelled onomatopoeia. An onomatopoeia is a word that sounds like what it is describing. A good example of this is the word quack. The sound that a duck makes is "Quack." The word sounds like the sound it is describing.
Onomatopoeia: Where sounds are spelled out as words; or, when words describing sounds actually sound like the sounds they describe. I heard him gurgling water.
It sounds like you are describing teaching.
Sounds like you're describing a hemisphere.
It sounds like you're describing the word "legit", which is short for (slang) "legitimate".