This page documents an OPTIMADE Unit Definition. See https://schemas.optimade.org/ for more information.

**ID: https://schemas.optimade.org/defs/v1.2/units/si/1970/temporary/knot**

`knot`

**Unit name:** knot

**Latin symbol:** knot

**Display symbol:** knot

**Description:** A unit of speed primarily used in navigation defined as 1 nautical mile per hour which is equal to (1852/3600) m/s using the 1967 SI units.

The knot unit appears in the International System of Units (SI), 1st ed. (1970) defined as "1 nautical mile per hour = (1852/3600) m/s."

- The International System of Units (SI), 1st ed. (1970) categorizes the unit as "Units in use temporarily with the International System."
- The International System of Units (SI), 7th ed. (1998) changes the categorization to "Other non-SI units currently accepted for use with the International System."
- The International System of Units (SI), 8th ed. (2006) changes the categorization to "Other non-SI units."
- The knot is omitted in the International System of Units (SI), 9th Edition (2019).

**Resources:**

- Definition in the International System of Units (SI), 1st Edition
- Wikipedia article describing the unit

**JSON definition:**

```
{
"$id": "https://schemas.optimade.org/defs/v1.2/units/si/1970/temporary/knot",
"$schema": "https://schemas.optimade.org/meta/v1.2/optimade/physical_unit_definition.json",
"title": "knot",
"symbol": "knot",
"display-symbol": "knot",
"description": "A unit of speed primarily used in navigation defined as 1 nautical mile per hour which is equal to (1852/3600) m/s using the 1967 SI units.\n\nThe knot unit appears in the International System of Units (SI), 1st ed. (1970) defined as \"1 nautical mile per hour = (1852/3600) m/s.\"\n\n- The International System of Units (SI), 1st ed. (1970) categorizes the unit as \"Units in use temporarily with the International System.\"\n- The International System of Units (SI), 7th ed. (1998) changes the categorization to \"Other non-SI units currently accepted for use with the International System.\"\n- The International System of Units (SI), 8th ed. (2006) changes the categorization to \"Other non-SI units.\"\n- The knot is omitted in the International System of Units (SI), 9th Edition (2019).",
"resources": [
{
"relation": "Definition in the International System of Units (SI), 1st Edition",
"resource-id": "https://www.bipm.org/en/publications/si-brochure"
},
{
"relation": "Wikipedia article describing the unit",
"resource-id": "https://en.wikipedia.org/wiki/Knot_(unit)"
}
],
"defining-relation": {
"base-units": [
{
"symbol": "m",
"id": "https://schemas.optimade.org/defs/v1.2/units/si/1960/base/metre"
},
{
"symbol": "s",
"id": "https://schemas.optimade.org/defs/v1.2/units/si/1967/base/second"
}
],
"base-units-expression": "ms^-1",
"scale": {
"numerator": 1852,
"denominator": 3600
}
},
"x-optimade-definition": {
"label": "knot_si_1970_temporary",
"kind": "unit",
"format": "1.2",
"version": "1.2.0",
"name": "knot"
}
}
```