Prunus and Plum tree

Prunus noun - A genus of shrubs and trees of the family Rosaceae that is widely distributed in temperate regions.

Plum tree and prunus are semantically related. In some cases you can use "Plum tree" instead a noun "Prunus".

Plum tree noun - Any of several trees producing edible oval fruit having a smooth skin and a single hard stone.

Prunus and plum tree are semantically related. You can use "Prunus" instead a noun phrase "Plum tree".