lemongrass Syllabification: (lem·on·grass)Pronunciation: /ˈleməngras/ (also lemon grass)Definition of lemongrass noun a fragrant tropical grass that yields an oil that smells lemon. It is widely used in Asian cooking and in perfumery and medicine. Cymbopogon citratus, family Gramineae lemongrass in other Oxford dictionaries Definition of lemongrass in the British & World English dictionary