Kissing is a common human behavior. They can be friendly, as in a greeting between friends, maternal between a mother and a child, or passionate exchanges of affection between lovers.

Kissing can be, and has been, talked about very poetically. Shakespeare for example, called a kiss “The Seal of Love”, and Coleridge called it “nectar breathing”. Martial, a Roman poet stated that a kiss was “the fragrance of balsam extracted from aromatic trees; amber warmed by the hand of a girl; a bouquet of flowers that attracts the bees” etc. (taken from Hugh Morris’ “The Art of Kissing”)

Kissing can also be talked about in very clinical terms, referring to the set of chemicals they produce and the effect those chemicals have on our bodies. The most well known love-related chemical is PEA (phenyl ethylamine) and is naturally occurring amphetamine released by not when we kiss, but also when we do other exciting things such as bungee-jumping, or eating chocolate J Other chemicals involved in the more passionate of activities are dopamine, which in turn encourages the production of oxytocin, which stimulates the cuddle-reflexes, and the euphoria-inducing chemical norepinephrine, which stimulates the production of adrenaline. The body is of course infested with nerve endings that are used to transport these chemicals as signals from the brain to our organs, making the skin tingle, stomach to do flip-flips, and …well, lighting loins on fire. Other researchers have found that kissing and hugging releases endorphins, giving mind and body a sense of genuine well being that is translated into better health.

There seem to be an inherent need to kiss the people we care about or feel love for. Some have argued that it is an instinct, while others have claimed that it is not more natural than wearing clothes (Vaughn Bryant, professor of anthropology at Texas A&M University in College Station), and that kissing is an act conditioned by cultural values. Nevertheless, kissing is an articulation in a language commonly known, signaling to onlookers that two people care for each other. In some cultures, kissing in public is taboo, and has also been declared a mortal sin by the Catholic Church in the middle ages.

kiss (Webster's dictionary)
To touch with the lips especially as a mark of affection or greeting.

kiss The American Heritage Dictonary
-v. kissed, kiss·ing, kiss·es
1. To touch or caress with the lips as a sign of sexual passion, affection, greeting, or respect. 2. To touch lightly; brush against. 3. To engage in mutal touching or caressing with the lips.
-n. 1.a A caress or touch with the lips. b. A slight or gentle touch. 2.a. A small piece of candy, esp. of chocolate. 2.b. A baked confection made of meringue.

French kiss (Webster's dictionary)
Date: circa 1923
An open-mouth kiss usually involving tongue-to-tongue contact. Also known as a Soul kiss.

Eskimo kiss
To touch the tips of each other's noses, and then rub back and forth.

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