relationship vs relation

relationship and relation both are nouns.

Word	Noun	Adjective	Verb	Adverb
relationship	Yes	No	No	No
relation	Yes	No	No	No

As nouns, relation is a hypernym of relationship; that is, relation is a word with a broader meaning than relationship:

relationship: a relation between people; (`relationship' is often used where `relation' would serve, as in `the relationship between inflation and unemployment', but the preferred usage of `relationship' is for human relations or states of relatedness)
relation: an abstraction belonging to or characteristic of two entities or parts together

As nouns, relation is a hypernym of relationship; that is, relation is a word with a broader meaning than relationship:

relationship: (anthropology) relatedness or connection by blood or marriage or adoption
relation: an abstraction belonging to or characteristic of two entities or parts together

relationship (noun)	relation (noun)
a relation between people; (`relationship' is often used where `relation' would serve, as in `the relationship between inflation and unemployment', but the preferred usage of `relationship' is for human relations or states of relatedness)	an abstraction belonging to or characteristic of two entities or parts together
(anthropology) relatedness or connection by blood or marriage or adoption	(usually plural) mutual dealings or connections among persons or groups
a state of connectedness between people (especially an emotional connection)	sexual activity between individuals, especially the insertion of a man's penis into a woman's vagina until orgasm and ejaculation occur
a state involving mutual dealings between people or parties or countries	(law) the principle that an act done at a later time is deemed by law to have occurred at an earlier time
	an act of narration
	a person related by blood or marriage