MUSIC GENRE
A music genre is a category (or genre) of pieces of music that share a certain style or "basic musical language". Music can also be categorised by non-musical criteria such as geographical origin.

POPULAR MUSIC GENRE
Blues - The Blues is a vocal and instrumental music form which emerged in the African-American community of the United States. Blues evolved from West African spirituals, work songs, field hollers, shouts and chants and has its earliest stylistic roots in West Africa. This musical form has been a major influence on later American and Western popular music, finding expression in ragtime, jazz, big bands, rhythm and blues, rock and roll and country music, as well as conventional pop songs and even modern classical music. Due to its powerful influence that spawned other major musical genres originating from America, blues can be regarded as the root of pop as well as American music.
Hip Hop/Rap - Hip hop music (also referred to as rap or rap music) is a style of popular music. It is made up of two main components: rapping (MCing) and DJing (audio mixing and scratching). Along with breakdancing and graffiti (tagging) these are the four elements of hip hop, a cultural movement that was initiated by inner-city youth (mostly minorities such as African Americans and Latinos) in New York City in the early 1970s. Typically, hip hop music consists of one or more rappers who tell semi-autobiographic tales, often relating to a fictionalized counterpart, in an intensely rhythmic lyrical form making abundant use of techniques like assonance, alliteration, and rhyme. The rapper is accompanied by an instrumental track, usually referred to as a "beat", performed by a DJ, created by a producer, or one or more instrumentalists. This beat is often created using a sample of the percussion break of another song, usually a funk, rock, or soul recording. In addition to the beat other sounds are often sampled, synthesized, or performed. Sometimes a track can be instrumental, as a showcase of the skills of the DJ or producer.
Rhythm and Blues - Rhythm and blues is a name for black popular music tradition. When speaking strictly of "rhythm 'n' blues", the term may refer to black pop-music from 1940s to 1960s that was not jazz nor blues but something more lightweight. The term "R&B" often refers to any contemporary black pop music. Early-1950s R&B music became popular with both black and white audiences, and popular records were often covered by white artists, leading to the development of rock and roll.A notable subgenre of rhythm 'n' blues was doo-wop, which put emphasis on polyphonic singing. In the early 1960s rhythm 'n' blues took influences from gospel and rock and roll and thus soul music was born. In the late 1960s, funk music started to evolve out of soul; by the 1970s funk had become its own subgenre that stressed complex, "funky" rhythm patterns and monotonistic compositions based on a riff or two. In the early to mid 1970s, hip hop music (also known as "rap") grew out of funk and reggae. Funk and soul music evolved into contemporary R&B (no longer an acronym) in the 1980s, which cross-pollinated with hip-hop for the rest of the 20th century and into the 21st century. POP Music - Pop music is a music genre which began in the 1950s, and is music that is generally popular to a wide range of people, hence "popular music". With the introduction of vinyl records in the 1930s, and later CDs (Compact Discs) in the 80s, recorded music became more widely available, as opposed to live music. Pop songs often make use of the 3-minute song to create hit records in the Pop Singles Charts (Billboard Hot 100). It uses melodies that are usually easily listenable, and therefore appeal to many. Pop music is characterised by a heavy rhythmic element, and often with the use of electronic amplification, while the melody line may also be dominant. It also refers to popular songs that people generally enjoy singing. It is commercially and radio friendly, readily accessible, memorable and easily marketable, often with a catchy chorus. It draws from a wide range of musical influences from pop/rock, R&B, country, soul, rock, jazz, folk and more.
Rock - Rock, in its broadest sense, can refer to almost all popular music recorded since the early 1950s. Its earliest form, rock and roll, arose from multiple genres in the late 1940s, most importantly jump blues. Although invented by Chuck Berry, it was first popularized by performers like Bill Haley, Buddy Holly, and Elvis Presley, who fused the sound with country music, resulting in rockabilly. In addition, gospel music and a related genre, R&B (rhythm and blues), emerged later in the decade. R&B soon became one of the most popular genres, with girl groups, garage rock and surf rock most popular in the US, while harder, more blues-oriented musicians became popular in the UK, which soon developed into British blues, merseybeat, mod and skiffle. Starting the mid-1960s, a group of British bands that played variations on American R&B-influenced blues became popular on both sides of the Atlantic - the British Invasion, a catchall term for multiple genres. These groups, including the Beatles, fused the earlier sounds with Appalachian folk music, forming folk rock, as well as a variety of less-popular genres, including the singer-songwriter tradition. Early heavy metal and punk rock bands formed in this period, though these genres did not emerge as such for several years.
Jazz - Jazz is a musical form that grew out of a cross-fertilization of folk blues, ragtime, and European music, particularly band music. It has been called the first native art form to develop in the United States of America. The music has gone through a series of developments since its inception. In roughly chronological order they are Dixieland, swing/big band, bebop, hard bop, cool jazz, free jazz, jazz fusion and smooth jazz. Jazz is primarily an instrumental form of music. The instrument most closely associated with jazz may be the saxophone, followed closely by the trumpet. The trombone, piano, double bass, guitar and drums are also primary jazz instruments. The clarinet and banjo were often used, especially in the earlier styles of jazz. Although there have been many renowned jazz vocalists, and many of the most well-known jazz tunes have lyrics, the majority of well-known and influential jazz musicians and composers have been instrumentalists. During the time of its widest popularity, roughly 1920 to 1950, jazz and popular music had a very intimate connection. Popular songs drew upon jazz influences, and many jazz hits were reworkings of popular songs, or lyrics were written for jazz tunes in an attempt to create popular hits. The single most distinguishing characteristic of jazz is improvisation. Jazz also tends to utilize complex chord structures and an advanced sense of harmony. These characteristics in combination with the use of improvisation require a high degree of technical skill and musical knowledge from the performers. The art form today is a widely varied one, using influences from all of the past styles, although the root of modern jazz is primarily bebop. Modern jazz can also incorporate elements of rock and roll, electronica, and hip-hop. Jazz was a direct influence on Rhythm and blues, and therefore a secondary influence on most later genres of popular music. Modern American art music composers have often used elements of jazz in their compositions.