A kiss is the act of pressing one's lips against the lips or other body parts of another person or of an object. Cultural connotations of kissing vary widely. Depending on the culture and context, a kiss can express sentiments of love, passion, affection, respect, greeting, friendship and good luck, among many others. In some situations a kiss is a ritual, formal or symbolic gesture indicating devotion, respect or greeting, as in the case of a bride and groom kissing at the conclusion of a wedding ceremony or national leaders kissing each other in greeting, and in many other situations.

Depending on the culture, relationship and context, a person may kiss another on their lips, cheek, head, hand and each of these gestures may carry a different social significance.

The word came from Old English cyssan (“to kiss”), in turn from coss (“a kiss”).

Kissing on another person's lips has become a common expression of affection among many cultures worldwide. Yet in certain cultures, kissing was introduced only through European settlement; prior to this, kissing was not a routine occurrence. Examples of this include certain indigenous peoples of Australia, the Tahitians, and many tribes in Africa.

A mountain is a large landform that stretches above the surrounding land in a limited area usually in the form of a peak. A mountain is generally steeper than a hill. The adjective montane is used to describe mountainous areas and things associated with them. The study of mountains is called orography. Exogeology deals with planetary mountains, which in that branch of science are usually called montes (singular—mons). The highest mountain on Earth based from sea level is Mount Everest (8,848 m (29,029 ft)) in the Himalayas of Asia. The highest known mountain in the Solar System is Olympus Mons on the planet Mars at 21,171 m (69,459 ft). Mountains and mountain ranges on Earth are typically formed by the movement and/or interaction of lithospheric plates.

There is no universally accepted definition of a mountain. Elevation, volume, relief, steepness, spacing and continuity have been used as criteria for defining a mountain. In the Oxford English Dictionary a mountain is defined as "a natural elevation of the earth surface rising more or less abruptly from the surrounding level and attaining an altitude which, relatively to the adjacent elevation, is impressive or notable."