Noun
middling plantation (plural middling plantations)
(US, historical) A medium-size plantation with about 20-49 slaves. Contrasted with small plantation or smallholding (19 or less slaves) and large plantation (50+ slaves).
"A planter or large plantation held fifty or more slaves while a middling plantation or slaveholder owned twenty to forty-nine slaves. Thus, a small plantation was one on which there were nineteen or fewer slaves." (Wilma P. Dunaway, Slavery in the American Mountain South: "Introduction" 9, 2003)