| Word | Description |
| Gallons Per Minute (GPM) | The amount of hot water in gallons a tankless water heater can supply per minute over a 77°F temperature increase; determined by the manufacturer using U.S. Department of Energy procedures. |
| Glazing | glass in a window or door, or the act or process of fitting with glass |
| Glucose | The human body converts most carbohydrates into a simple sugar called glucose. Glucose is a major source of energy for most cells of the body. It is the main sugar that the body makes from most carbohydrate foods and uses for fuel. Cells cannot use glucose for fuel without the help of insulin, a hormone which is made by the pancreas. |
| Glycemic Index: | A measure of how rapidly glucose of various forms of carbohydrates are absorbed into the blood circulation. |
| Grafted | A way to reproduce plants with the joining of parts of plants together in such a way that they unite and continue their growth as one plant. |
| Granulation | drying of the juice sacs within fruit |
| Grilling | A cooking technique in which foods are cooked directly over flame or the heat source by radiant heat placed below the food. Grills may be fueled by gas, electricity, charcoal or wood. Direct heat cooking usually at temperatures of 350F or more. Grilling is hot and fast cooking. Also, the piece of equipment on which grilling is done. |
| Groundcover | A ground cover is any low-growing plant that can be used to cover an area in the landscape. |
