# Ontology of units of Measure (OM)

> The Ontology of units of Measure (OM) 2.0 models concepts and relations important to scientific...

- Page: https://library.schematica.io/model/ad1f1f867b3944dfa01a2d9409cf8dce
- Model type: Ontology
- License: CC BY 4.0
- Access type: Free
- Access method: Download
- Model size: Small
- Formats: OWL
- Domains: Tech / IT
- External link: https://bioportal.bioontology.org/ontologies/OM
- Contact: Hajo Rijgersberg (hajo.rijgersberg@wur.nl)
- Listed in library: 2025-06-12
- Last updated: 2025-09-10

## Description

## Ontology Info

| Field | Value |
|-------|-------|
| Acronyme | OM |
| Description | The Ontology of units of Measure (OM) 2.0 models concepts and relations important to scientific research. It has a strong focus on units, quantities, measurements, and dimensions. OM is modelled in OWL 2 - Web Ontology Language. The OM ontology provides classes, instances, and properties that represent the different concepts used for defining and using measures and units. It includes, for instance, common units such as the SI units metre and kilogram, but also units from other systems of units such as the mile or nautical mile. For many application areas it includes more specific units and quantities, such as the unit of the Hubble constant or the quantity vaselife. The following application areas are supported by OM: Geometry; Mechanics; Thermodynamics; Electromagnetism; Fluid mechanics; Chemical physics; Photometry; Radiometry and Radiobiology; Nuclear physics; Astronomy and Astrophysics; Cosmology; Earth science; Meteorology; Material science; Microbiology; Economics; Information technology and Typography. |
| Format | OWL |
| Categories | Other, Plant |
| Groups |  |

## Metrics

| Metric | Value |
|--------|-------|
| Classes | 814 |
| Individuals | 2,251 |
| Properties | 34 |
| Max Depth | 4 |
| Max Child Count | 207 |
| Average Child Count | 9 |
| Classes With One Child | 25 |
| Classes With More Than 25 Children | 4 |
| Classes With No Definition | 485 |

## Projects using OM

No projects using OM

---

Source: https://library.schematica.io/model/ad1f1f867b3944dfa01a2d9409cf8dce