Scuba & Nitrox Glossary: Z
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 — Z
- Zero Calibration
- Setting an analyzer’s zero point according to the manufacturer’s procedure.
- Zero-Oxygen Gas
- A gas without oxygen, sometimes used for analyzer testing or specialized blending; it is not breathable.
- Zero Drift
- Change in an analyzer's zero reference over time.
- Zero-Gas Calibration
- Establishing an analyzer baseline with a gas containing no oxygen.
- Zero-Pressure Blend Plan
- A blending calculation that assumes an empty, depressurized cylinder.
- Zirconia Oxygen Sensor
- A heated sensor technology used in some oxygen-measurement applications.
- Zone Filling
- Separating fill-station work areas by gas type, cleanliness, or hazard control.
General Scuba Terms — Z
- Z-Factor
- A compressibility factor correcting ideal-gas calculations for real-gas behavior at high pressure.
- Zipper Care
- Cleaning, lubrication, storage, and operation practices that protect drysuit zippers.
- Zone of Caution
- A nonstandard descriptive phrase for conditions approaching an equipment, gas, or exposure limit; use explicit limits instead.
- Zebra Mussel
- An invasive freshwater mollusk that can create sharp surfaces at dive sites.
- Zigzag Search
- A back-and-forth search pattern used to cover an area.
- Zip Tie
- A fastening device that can secure equipment but may create sharp edges or entanglement points.
- Zodiac-Style Boat
- A rigid or soft inflatable boat commonly used for dive operations.
- Zooplankton
- Small drifting animals that can affect visibility and attract marine life.