A dive is the stay of a diver under water. Thereby, not only the time under water counts, but also the preparation for it. There are different types of dives. Among them are:
Standard dive: These begin with descending in water. Some definitions suggest, that this begins when you put on your equipment. If you briefly resurface and after less than 10 minutes descend again, your dive is considered to be interrupted. The time that you spend under water afterwards does not count as a new try.
Repetitive dive: If you dive again more than 10 minutes after your last stay under water and your tissue is not completely saturated yet, this counts as a repetitive dive. You must prepare yourself particularly well for this, because it is linked to a higher risk. In general, the no-deco-time is prolonged due to the nitrogen stress on the tissue.
When descending you will find yourself in the so-called compression phase. Your body must first adapt to the higher ambient pressure. By the way, the risk of a barotrauma is above average during this phase.
When you have reached your desired diving depth, the so-called isopression Here the ambient pressure is constant.