(metrology) A standard set of units of measurement for use in scientific literature worldwide. The newest and most widespread version of the metric system.

(computing, historical) A type of computer system, now largely obsolete, used to exchange messages and data over a telecommunications network.

(aviation) A collection of radio navigation aids (always including a localizer and glideslope, and often one to three marker beacons as well) used by pilots for approach guidance to a specific airport runway, especially when visibility is limited.

A navigation system that produces hyperbolic lines of position by the measurement of the difference in the time of reception, or the phase, of radio signals from multiple synchronized transmitters at fixed locations.

(rare, organic chemistry) Any organic compound, in the form of a ring, that has the maximum number of noncumulative double bonds; e.g. benzene or indole.

(computing) A computer software system for organizing and facilitating collaborative creation of documents and other content, especially for loading to a website

(neuroanatomy) One of the divisions of the autonomic nervous system, based between the brain and the spinal cord, that slows the heart and relaxes muscles.

(computing, Internet) The distributed database, sometimes including all the supporting hardware or software infrastructure, the Internet uses to translate hostnames into IP addresses and provide other domain-related information.

Any assemblage of equipment used to generate, store and distribute electrical power on board a satellite or spacecraft

Any electronic navigation system which uses space satellites as radio signal sources and position references. / A satellite network used for implementing such a system.