Attribute Data: Tabular or textual data describing the geographic characteristics of features. 
Base Map/Base Layer: A primary layer for spatial reference, upon which other layers are built. Examples of a base layer typically used are either the parcels, or street centerlines. 
Bottom-Up: Bottom-up research approaches emphasize the power and agency of individuals to shape society, as opposed to approaches which view individuals as a product of the society in which they live. Bottom-up management emphasizes grassroots activism and action.
Cartography: The science or practice of creating visual representations of geographic areas, such as on maps.
Cognitive Mapping: Cognitive maps are mental representations of physical locations. While cognitive maps are not necessarily spatially accurate, they can reveal how people use spaces and what they perceive to be important or unimportant.
Community Mapping: See Public Participatory GIS
Critical Cartography: Critical cartography uses approaches from traditional cartography and geography to examine power dynamics within societies.
Crowdsourcing: Crowdsourcing is a type of data collection in which a large group of people is solicited to work toward a common goal. Often crowdsourcing is done via the internet.
Decision Support Systems: Decision support systems can refer to a number of different tools, processes or programs (typically computer-aided) which support of more informed decision making.
Ecosystem Services: Benefits people derive from ecosystems.
Geodatabase: A database or file structure used primarily to store, query, and manipulate spatial data. Geodatabases store geometry, a spatial reference system, attributes, and behavioral rules for data. Various types of geographic datasets can be collected within a geodatabase, including feature classes, attribute tables, raster datasets, network datasets, topologies, and many others. 
Geodesign: an approach to city planning, land use and natural resource management that takes into account the tendency in recent years to overdevelop land at the expense of natural habitats, as well as population growth and climate change
Georeferencing: The process of assigning real-world coordinates to a map or image for spatial analysis.
IPBES: Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services
ISPM: International Society for Participatory Mapping
Landscape Values: Different stakeholder groups have different wants and needs from the landscape, leading to a diverse range of landscape values. This diversity of demands, perceptions, and uses of landscapes raise challenging questions about how to best design, plan, and manage resilient landscapes that are resistant to shocks and adaptive to changes in society and environment.
Legend: A map legend is a visual graphic of the symbology used in a map that tells the map reader what the polygons, lines, points or grid cells represents.
Mental Mapping: (please see Cognitive Mapping)
Open-Access: The free, immediate, online availability of research or resources and the right to use these research or resources freely.
Open Data: research data that is freely available on the internet permitting any user to download, copy, analyse, reprocess, pass to software or use for any other purpose without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself.
Open Data Kit (ODK): a free and open-source set of tools which help organizations author, field, and manage mobile data collection solutions.
Open-Source: The term “open source” refers to something people can modify and share because its design is publicly accessible.
OpenStreetMap: OpenStreetMap (OSM) is a collaborative project to create a free editable map of the world.
Participatory GIS (PGIS): Participatory GIS draws on the diversity of experiences associated with ‘participatory development’ and involves communities in the production of GIS data and spatial decision-making.
Proprietary: In contrast to open source software or resources, proprietary software is commercially owned and use/access are guarded and limited.
Public Participation GIS (PPGIS): The idea behind PPGIS is empowerment and inclusion of marginalized populations, who have little voice in the public arena, through geographic technology education and participation. PPGIS uses and produces digital maps, satellite imagery, sketch maps, and many other spatial and visual tools, to change geographic involvement and awareness on a local level. [I LIKE THIS DEFINITION THOUGH WIKIPEDIA IS THE SOURCE – PLEASE HELP IMPROVE]
Scale: The ratio or relationship between a distance or area on a map and the corresponding distance or area on the ground.
Sense of Place: Broadly speaking, sense of place refers to people’s emotional attachment to places and the meanings that people give to those places.
Sketch Mapping: Generally, sketch maps are spatially referenced (cartographically accurate) maps that represent the unique and varied lived experiences of social groups, households, or individuals.
Top-Down: Top-down social research tends to view individuals as products of the societies in which they live. Top-down management emphasizes authoritative decision-making at higher levels of governance.
Ushahidi: A company and open source participatory mapping platform based in Kenya. Started in 2008 during street violence after presidential elections in Kenya as a tool for reporting and visualisation, Ushahidi is often used as a tool for citizen reporting for humanitarian and citizen science projects.
Volunteered Geographic Information (VGI): the harnessing of tools to create, assemble, and disseminate geographic data provided voluntarily by individuals.
References (Great GIS basic terminology resources)