If something is visible to many people then, collectively, they are more likely to find errors in it. Publishing open data can therefore be a way to improve its accuracy and data quality, especially where a good interface for reporting errors is provided. See → crowdsourcing.

Source: ODH

The combination of multiple datasets from multiple sources to create a new service or visualisation or new information. 

Source: EU OD

Data in a data format that can be easily automatically read and processed (or identified, recognized and extracted) by a computer, without human intervention, including individual statements of fact, and their internal structure, while ensuring no semantic meaning is lost. Examples of file formats are CSV, JSON, XML, etc. Machine-readable data must be structured data. 

Machine learning (ML) is the scientific study of algorithms and statistical models that computer systems use to perform a specific task without using explicit instructions, relying on patterns and inference instead. It is seen as a subset of artificial intelligence. Machine learning algorithms build a mathematical model based on sample data, known as "training data", in order to make predictions or decisions without being explicitly programmed to perform the task.

Linked data principles provide a common API for data on the web that is more convenient than many separately and differently designed APIs published by individual data suppliers. Tim Berners-Lee, inventor of the web and initiator of the linked data project, proposed the following principles upon which linked data is based. Use URIs to name things. Use HTTP URIs so that things can be referred to and looked up (dereferenced) by people and user agents.

A form of data representation where every identifier is an http://… URI, using standard lists (see vocabulary) of identifiers where possible, and where datasets include links to reference datasets of the same objects. A key aim is to make data integration automatic, even for large datasets. Linked data is usually represented using RDF. See also five stars of open data; triple store. Source: ODH

If Project X publishes content, and wants to include content from Project Y, it is necessary that Y’s licence permits at least the same range of re-uses as X’s licence.

A legal instrument by which a copyright holder may grant rights over the protected work. Data and content is open if it is subject to an explicitly-applied licence that conforms to the Open Definition. A range of standard open licences are available, such as the CCZero licence or the Creative Commons CC-BY licence, which requires only attribution.

Keyhole Markup Language, an XML-based open format for geodata. KML was devised for Keyhole Earth Viewer, later acquired by Google and renamed Google Earth, but has been an international standard of the Open Geospatial Consortium since 2008.

Source: ODH.

JSON-based format to serialize Linked Data. The syntax is designed to easily integrate into deployed systems that already use JSON, and provides a smooth upgrade path from JSON to JSON-LD. It is primarily intended to be a way to use Linked Data in Web-based programming environments, to build interoperable Web services, and to store Linked Data in JSON-based storage engines.