Foreplay is commonly used to refer to sexual activities that take place prior to intercourse. There are no official or universally agreed upon details about what kinds of activities would be included in foreplay, or if everything other than intercourse counts.
While the term has been used at least since the early 1900s, it became a focus of sexual technique writing, teaching, and therapy following the research writing of Alfred Kinsey, and the clinical research by sex therapists Masters and Johnson. Collectively these sexologists pointed to the importance of sex play being more than just intercourse, and specifically that for women, intercourse was often not enough to achieve orgasm, and without being turned on it may not be pleasurable at all.
More recently, some sex educators and therapists have critiqued the term foreplay as it presumes that intercourse is always the main event of any sexual situation. Even the name seems to suggest that activities ranging from kissing to erotic touch, oral sex to dirty talk, are all less important than intercourse, just the lead up to the "real deal".
Whether you like the term or not, most professionals agree that sex is more than intercourse and foreplay is more than just a pre-amble to sex.