greenhouse emission green·hou·see·mission uncommon noun 1. a gas that contributes to the greenhouse effect by absorbing infrared radiation Synonymsgreenhouse gasgreenhouse emission Related words Broader terms gas Narrower terms chlorofluorocarboncarbon dioxidehydrofluorocarbonperfluorocarbonsulfur hexafluoride WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.