A honky-tonk (also called honkatonk, honkey-tonk, or tonk) is both a bar that provides country music for the entertainment of its patrons and the style of music played in such establishments. The first music genre to be commonly known as honky-tonk was a style of piano playing related to ragtime but emphasizing rhythm more than melody or harmony. In the years before World War II, the music industry began to refer to honky-tonk music played from Texas and Oklahoma to the West Coast as hillbilly music. More recently, the term has come to refer to the primary sound in country music, developing in Nashville as Western swing became accepted there. Originally, it featured the guitar, fiddle, string bass, and steel guitar (imported from Hawaiian folk music). Lyrics tended to focus on working-class life, with frequently tragic themes of lost love, adultery, loneliness, alcoholism, and self-pity.

Source: Wikipedia