Pet names are used to show affection and endearment towards someone. There are many synonyms for pet names, such as nicknames, endearments, terms of endearment, and sweet names. These words are often used interchangeably and can be utilized in different situations. "Nickname" is the most common synonym used for a pet name, both in informal and formal settings. "Endearment" and "term of endearment" describe a pet name that is given to someone with fondness and respect. Lastly, using "sweet names" is synonymous with pet names and describes those given to a loved one, family member, or friend as a sign of affection and fondness.