From The All Music Guide/Glossary: (I hope this counts as "fair use.")

Call and Response

Call and response in essence is a colloquial jazz name for a type of antiphonal music. Extensive or abbreviated musical passages are played by one person, choir or group of musicians and then those passages are copied, mimicked, varied or answered by another person, choir or group of musicians. Call and responses can also occur between an individual and a group. Afro-American work songs, generated during the slave days and later, were often call and response pieces. A single individual would call out to the others as if demanding a response. The rest of the people would answer the call. Religious themes were often the dominant force behind the songs with calls for salvation and liberation. (Of course the apparent themes and the coded themes were related, but different regarding what the "crew-chief" heard and the singers meant. The familiar "Amen" is a call response song as are military marching cadences. In jazz, call and responses are most often used between two instrumentalists as they trade measures in riff passages. Call and response can also occur between a singer and an instrumentalist a practice often found in the practice of scat singing.

Antiphonal

From the Greek "anti" against and "phon" sound, this adjective describes any music in which two voices or groups are singing against one another, not in a competitive sense, but in response to one another. It was formerly rarely employed to describe instrumental music as its roots developed within the context of choral music. Choirs or ensembles were divided into two or more distinct groups in an antiphonal piece of music. They most often perform in sequences of music that are combined and then separated in an alternating fashion. One group will sing and then be echoed, mirrored, or responded to by the other group. Antiphon was first employed as a referent to octaves or double octaves where men's voices are alternated with women's voices and/or boy's voices. As music developed the term antiphonal was used to refer to any music alternation between two groups, vocal or not.

Chorus

The repeated section -- refrain -- of a song that follows each of the verses is referred to as the chorus of the song. The term is also used to refer to any group of singers, most often male and female, who perform together, either in unison or in parts. Though no clear distinction is made between a chorus and a choir, the latter term is most often used to refer to groups that sing sacred music and the former to refer to groups of singers that perform secular music. This is a useful distinction though not always clearly defined. In jazz, chorus is used to denote a solo statement of the main theme, which often includes a series of variations based on that theme. Chorus in jazz parlance has a number of other references. Normally a chorus means going through the entire number one time, whether that means as few as twelve bars (as in a standard twelve bar blues) or as many as thirty two bars (typical AABA pattern), or, any other number of measures. In the jazz lexicon the use of chorus dates back to the days when popular songs contained a verse that could be tossed or omitted, followed by "the chorus." It is often used in critical parlance to refer to an extended solo chorus; for example, on Paul Gonsalves' celebrated performance at the 1956 Newport Jazz Festival. Jazz bands will often play the chorus through once, as stated, and then improvise upon the chord changes and progressions of those opening bars, until they return home to play the original "straight" chorus once again to bring the piece of music to a close.

Refrain

Though refrains can refer to elements of instrumental music, they are more appropriately associated with vocal music. Refrains are regularly repeated sections of music that most often occur in larger forms of music. Typical strophic songs will contain a number of verses, often scored for soloists, each one of which is followed by a refrain sung by a chorus. Refrains are found in a wide variety of music including ballads, carols, madrigals, rondeaus and virelai.