Guacamole can informally be referred to as "guac" in North America. It is an avocado-based dip or salad first created by the Aztecs in what is now Mexico. In addition to its use in modern Mexican cuisine, it has also become part of American cuisine as a dip, condiment and salad ingredient.

The name comes from an Aztec dialect via Nahuatl āhuacamolli, which literally translates to "avocado sauce".

Guacamole dip is traditionally made by mashing ripe avocados and sea salt with a molcajete (mortar and pestle). Some recipes call for tomato, onion, garlic, peas, lemon or lime juice, chili or cayenne pepper, coriander (also known as cilantro) or basil, jalapeño, and/or additional seasonings. Some non-traditional recipes call for sour cream as the main ingredient.

More Info: en.wikipedia.org