Kissing is a physical act where two people press their lips together, often as a sign of affection or greeting. It can vary in style and meaning across different cultures. For example, in some places, a kiss on the cheek is a common way to say hello, while in others, a romantic kiss may be more prevalent. The act of kissing can trigger the release of hormones like oxytocin, which promotes bonding and feelings of closeness. Kissing can also serve as a way to express love, passion, or friendship, making it a significant gesture in human relationships.