Scuba & Nitrox Glossary: X
Nitrox and breathing-gas terminology is prioritized first. General scuba terms follow below. Definitions are educational summaries and do not replace formal training, manufacturer instructions, or an operational dive plan.
Nitrox & Gas Terms — X
- x in EANx
- A placeholder for the oxygen percentage in enriched air; EAN32 means approximately 32% oxygen.
- XO₂ Display
- A notation used by some instruments or references for oxygen fraction; FO₂ is more common in dive training.
- X-Ray Cylinder Inspection
- Radiographic inspection used in specialized circumstances to examine cylinder structure.
- Xenon Contamination
- A rare-gas contamination concern relevant to specialized gas purity, not routine Nitrox.
- XO2 Display
- A generic notation sometimes used by instruments for oxygen concentration; verify the device convention.
- X-Over Fill
- Informal shorthand for a crossover transfer between gas cylinders.
- X-Y Gas Plot
- A graph comparing expected and measured gas values during analyzer evaluation.
General Scuba Terms — X
- X-Over
- Informal shorthand for a crossover course recognizing prior certification while training under another agency.
- Xenon
- A noble gas with strong narcotic properties; not a practical recreational breathing gas.
- X-Axis Compass Error
- Side-to-side instrument alignment error that can affect a compass heading.
- X-Pattern Search
- A crossing search route used to inspect a compact area.
- Xenobiotic Exposure
- Contact with a foreign chemical substance that may affect diver health.
- Xeric Shore Entry
- An entry across a dry, arid shoreline where heat management is important.
- Xiphoid Process
- The lower sternum area where poorly placed equipment can cause pressure or discomfort.