What “One love” means
One love expresses unity, love and respect between people. It's often used as a farewell, a bit like "peace", and it carries the idea that everyone is connected.
Examples
One love
Peace / Goodbye
One love, mi bredda.
Peace, my brother.
How to use it
Said when parting or to close a conversation on a warm note. It's friendly and sincere rather than slangy, and visitors can use it comfortably.
Cultural context
The phrase was made famous worldwide by Bob Marley, and reggae spread its message of unity far beyond Jamaica.