Expression of peace, love and Unity. 'Olivu' means 'olive' in many languages and so has an association with the olive branch, a symbol of peace. The letters rearranged make 'i lov u', the text message version of 'I love you'. The capital 'U' comes from the 'u' shape formed by the thumb and fingers raised up as an symbol of Unity.
To show that you want to end an argument say "olivU!" (say o-li-vu) and raise the thumb and fingers to form a 'U' shape. If the other person accepts the peace offer they will raise a U to link with yours so that the palms interlock with each other and the forearms are at 90 degrees to each other.