Geodesy : Branch of applied mathematics that specializes in measuring the Earth to determine its shape and size.

Geology : The study of the physical properties of the solid and liquid materials that make up the Earth, their history, and the processes that create and change them.

Geophysics : The study of the entire Earth as a whole using quantitative instruments and the principles of physics.

Geosciences; earth sciences: An umbrella term for all the sciences that are devoted to studying the planet. Typically divided into four fields: geography, geology, geophysics, geodesy.

Geothermal energy : Clean, reliable, renewable resource that taps the heat from the core of the Earth to generate electricity and provide heating and cooling applications. Geothermal energy is divided into three categories: geothermal electricity production, geothermal direct use, geothermal heat pumps.

Glaciology : Branch of hydrology that focuses on glaciers.

Green: Generally used as shorthand for something that improves the state of the environment in a discernable way. Can refer to a product, industry, company, job, process, or organization that conserves energy and resources, generates clean, renewable energy, minimizes waste, eliminates hazardous materials, or restores the environment and biodiversity.

Green economy: The industries that are producing greener products, using cleaner processes, and offering more sustainable services in an effort to move us toward a new standard.

green marketing; environmental marketing; ecological marketing: Marketing practices that emphasize a company’s corporate social responsibility initiative; the marketing story may also include a description of the social impact of the product on the communities of the suppliers, producers, and end users.

Green-washing: Marketing practices that lead the consumer to believe that a product or service is beneficial to the planet even though it’s not.