Peasant technically just means somebody who lives in the countryside, as opposed to the city, and is generally not a landowner - I. E. They are renting their land or are serfs etc. They are generally not a paid labourer and instead use the land they rent to grow food primarily for their family, perhaps paying some of their produce as rent rather than money. This is rare in a market based economy where land is used more efficiently.

Was it David Harvey, by any chance? I got tripped up a little reading The Enigma of Capital and the Crises of Capitalism because he uses the word "peasants" specifically to describe remote agrarian populations that have not been, in his phrasing, "proletarianized", or integrated into the global capital exchange.