Son is a generic term for the musical family of country music originating in Oriente de Cuba (Eastern Cuba), as well as a style within the family itself.
Traditionally, Son was played with an ensemble similar to a Changüi, but the Contra Bass replaced the Marimbula and the Guayo was replaced by the Güiro and or the Maracas. Also, it is the first time that clave as we know play it is really present
Another characteristic of Son is that it doesn't generally have the second section or montuno. That is correctly called son-montuno, but in practice the terms are often interchanged.
Modern Son has taken on many offshoots including Songo, Timba and Son Moderno. These styles often mix Afro-Cuban rhythms such as Guaguanco and Funk along with a much freer use of Clave and patterns. Many patterns are actually "contra tumbao" or counter tumbao.