Precisely is defined as exactly, specifically or with precision. ... When it is exactly 1:00, this is an example of a time when it is precisely 1:00. When you carefully place books on a shelf with great precision, this is an example of a time when you place the books precisely on the shelf.
When you take blood pressure, it is expressed in a fraction. The top number of that fraction is systolic pressure- the amount of pressure in your arteries during contraction of your heart muscle... I hope this helped! :)