Maritime Glossary
Source-cited definitions for shipping, engineering, navigation, and regulatory terminology. Confidence-scored and verified against primary IMO, IHO, and industry sources.
- NOxnitrogen oxides · nitric oxide · NO · NO₂
- NOx means nitrogen oxides, a group of gases formed when fuel is burned at high temperature in a ship's engines. They contribute to air pollution, acid rain and smog, and are limited on ships by MARPOL Annex VI through progressively stricter tiers.
- environmentregulationengineeringhigh confidence
- Nautical MileNM · nmi · sea mile
- A unit of distance used at sea and in the air, equal to exactly 1,852 metres. It was originally defined as the length of one minute of arc of latitude along a meridian, which ties distance directly to a position on the globe.
- navigationseamanshiphigh confidence
- Net TonnageNT · net register tonnage · NRT
- Net tonnage is a dimensionless measure of a ship's useful cargo-carrying volume, derived from the gross tonnage by deducting the spaces not available for cargo. It is widely used as the basis for port dues, canal tolls and other charges.
- commercialregulationhigh confidence
- Notice of ReadinessNOR
- A Notice of Readiness (NOR) is a formal declaration by the ship that it has arrived at the agreed place and is ready in all respects to load or discharge the cargo. A valid NOR is what starts the laytime clock under a voyage charter.
- commercialcharteringlegalhigh confidence