"Chan" is a diminutive suffix in japanese language. It expresses that the speaker finds a person endearing. In general, chan is used for babies, young children, close friends, grandparents and sometimes female adolescents. "Chan" is only used between people who have known each other for a long time or who are of the same gender. Otherwise, using this for someone, especially adults, only known for a short period of time, can be seen as offensive. Some people adopt the childlike affectation of referring to themselves in the third person using chan (a young woman named Gogo might call herself Gogo-chan rather than using a first person pronoun).