http://es.wikipedia.org/wiki/Bienes_gananciales
Bienes gananciales
"Se denominan bienes gananciales o simplemente gananciales en derecho, a todos aquellos bienes adquiridos por los cónyuges durante el matrimonio, a excepción de los recibidos a título gratuito.
La característica principal de dichos bienes es que pertenecen a ambos cónyuges por igual, independientemente de quién de los dos los haya obtenido y lo normal es que para disponer de ellos baste con que el negocio jurídico lo acuerde uno de los dos cónyuges siempre y cuando exista la aceptación del mismo por parte del otro cónyuge."

http://www.lectlaw.com/def/c075.htm
COMMUNITY PROPERTY
Property acquired by a couple during their marriage. Refers to the system in some states for dividing the couple's property in a divorce or upon the death of one spouse. In this system, everything a husband and wife acquire once they are married is owned equally (fifty-fifty) by both of them, regardless of who provided the money to purchase the asset or whose name the asset is held in.

http://family-law.freeadvice.com/divorce_law/1community_prop...
"These states generally regard as community property all property that has been acquired during the marriage, other than a gift or inheritance. Even if one spouse earns all the money to acquire the property, all the property acquired is considered to be community property. While there are a number of differences in each state, all states have special laws that operate on the theory that both spouses contribute equally to the marriage; thus all property acquired during the marriage is the result of the combined efforts of both spouses. In community property jurisdictions, spouses equally own all community property (fifty percent owned by the husband and fifty percent owned by the wife). "