The term 'grain-fed' is a compound word formed from 'grain' and 'fed', where 'grain' refers to the seeds of cereal plants and 'fed' is the past participle of 'feed'.

The term 'grain-fed' has been used in modern English to describe livestock feeding practices, particularly in the context of agriculture and food production.

Initially, it simply described the diet of animals, but over time it has come to imply certain qualities in the meat, such as marbling and flavor.