Citrus limon and Citrus tree

Citrus limon noun - A small evergreen tree that originated in Asia but is widely cultivated for its fruit.

Citrus tree and Citrus limon are semantically related. In some cases you can use "Citrus tree" instead a noun phrase "Citrus limon".

Citrus tree noun - Any of numerous tropical usually thorny evergreen trees of the genus Citrus having leathery evergreen leaves and widely cultivated for their juicy edible fruits having leathery aromatic rinds.

Citrus limon and citrus tree are semantically related. Sometimes you can replace phrase "Citrus limon" with "Citrus tree", this phrases are similar.