WOB – work of breathing

The work of breathing or WOB is in simple terms, the effort required by the lungs to breathe. But to be more accurate it refers to the energy expended to inhale and exhale a breathing gas. The WOB is usually expressed as work per unit volume.


The process known as “upwelling” is caused by the winds blowing across the surface of the ocean and push water away. Colder water then rises up from deeper beneath the surface to take the place of the water that was pushed away. It is also the opposite of downwelling.

Quick release

A quick release is a form of clip used for diving equipment. It is usually associated with a weight system but applies to many other purposes such as the releases of shoulder straps.


A rattle in diving is a piece of equipment designed to get attention by making a rattling sound. It is usually a hollowed tube with both ends plugged and containing metal balls. Shaking it create a sound from the shock of the balls.

Octopus – Octo (gear)

The Octopus or Octo is another name to designate the alternate air source on a diver regulator set. It comes from the first brand to introduce it Aqualung and named it Octopus. They also introduced the bright yellow color that almost all alternate regulator now has.

lb – lbs

lb or lbs are the short unit designation for pounds. It is a measurement of weight coming from the imperial system of units. One pound is equal to exactly 0.453592 kilograms.


Heliox is a breathing gas mixture used in technical and commercial diving. Heliox is composed of Oxygen and Helium only. Having no Nitrogen it avoid nitrogen narcosis that happens in deeper dives.

Equalize, Equalization

To equalize or equalization is the act of applying the same pressure in an air space than the one of the surrounding or ambient pressure. Usually, in diving, it refers to the ears but can also apply to the mask or even to the lungs.