French kiss, also known as deep kissing or tongue kissing, is a passionate form of kissing that involves the touching of tongues. Although this term is widely recognized, there are several other synonyms used to refer to this intimate act. Some other words commonly used include soul kiss, open-mouthed kiss, lip lock, tongue tango, and slippery smooch. The use of these alternative terms may depend on personal preference or cultural factors. Regardless of the name used, French kissing is a way to express affection and deepen intimacy between partners.