Definition from Wiktionary, the free dictionary
With reference to classical myth, where the olivebranch was a symbol of peace and prosperity, merging with Biblical allusion to Genesis 8:11, where a dove returns to Noah's ark as a sign that the Flood is subsiding.
- Used other than as an idiom: A branch of an olive tree.
- Such a branch offered as an emblem of peace.
- Any symbol of peace, or peace offering to an adversary to show good will and in the hope of securing peace.
- His remarks came after Britain offered a diplomatic olive branch to Iran earlier in the day to try to secure an early release of the prisoners. - The Observer, Iran snubs UK olive branch, 01/04/2007 
- I come bearing an olive branch in one hand, and the freedom fighter's gun in the other. Do not let the olive branch fall from my hand - Yasser Arafat
branch of an olive tree
branch as emblem of peace