topsoilPronunciation: /ˈtɒpsɔɪl/Translate topsoil | into German | into Italian | into Spanish Definition of topsoil noun [mass noun] the top layer of soil: keep all the topsoil you remove; you’re bound to find a use for it later! [count noun]:dry topsoils are typical in the western Corn Belttopsoil in other Oxford dictionaries Definition of topsoil in the US English dictionary