Meronymy and holonymy

In linguistics, meronymy (from Greek μέρος, "méros", "part", and ὄνυμα, "ónuma", "name") is a semantic relation between a meronym denoting a part and a holonym denoting a whole. In simpler terms, a meronym is in a "part-of" relationship with its holonym. For example, "finger" is a meronym of "hand" which is its holonym. Similarly, "engine" is a meronym of "car" which is its holonym.
Holonymy (from Greek ὅλος, "hólos", "whole", and ὄνυμα, "ónuma", "name") is the converse of meronymy.
A closely related concept is that of mereology, which specifically deals with part–whole relations and is used in logic. It is formally expressed in terms of first-order logic. A meronymy can also be considered a partial order.
A meronym refers to a "part". A hyponym refers to a "type". For example, a meronym of "tree" is "bark" or "leaf" (a part of tree), but a hyponym of "tree" is "pine tree" or "oak tree" (a type of tree).