The term "culture" can have at least two meanings in the context of civilization.
First, it can refer to the whole set of learned behaviors that are typical of a given society. In other words "culture" could refer to everything from the technologies that a society uses to the religious beliefs that it holds to the way it treats its children. Used in this sense, culture is a vast idea that encompasses pratically everything about a civilization.
Second, "culture" can refer to what we might call "higher culture." In this sense, it could refer to the arts and to intellectual life. Used in this sense, we would say that culture makes a civilization more "civilized." Culture takes a mere society and makes it into a civlization because culture shows that a society is interested in things beyond mundane everyday life.
by culture of historic civilizations we mean the lifestyle of the people of that time. this includes their behaviour, art, their social structure. it basicaly means their everyday life.