In English (New Zealand at least) "relation" is more common than "relative" in such contexts.
But as far as Greek is concerned, relation translates to συγγένεια/σχέση. So, you'd either have to say
You and I have a relation- Εγώ κι εσύ έχουμε συγγένεια or
You and I are relatives/are related - Εγώ κι εσύ είμαστε συγγενείς,
in order for the sentence to make sense in Greek. ^.^
"relation" has several meanings -- it can refer to a family relationship, or to a person who is connected to you by a family relationship.
For example, in "Winnie the Pooh", Rabbit has a lot of "friends and relations" (i.e. relatives).
Compare e.g. definitions 4 and 5 at http://www.dictionary.com/browse/relation .
No, that would be wrong. Look at the top of this page for the correct sentences.
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