Faith, Learning, and the Christian Worldview states, "A worldview is a set of assumptions or beliefs about reality that affect how a person think and how people live.
The term is fairly well described in the subtext to the question. One important addition might be that a person uses this "set of assumptions and beliefs" to provide a framework within which they can understand their world. The concept of a worldview does not mean that a person has all the answers, but it does set the context, or even the limits, of how a person might attempt to answer the questions they face in their lives.
For example, thinking about fundamental issues relating to life's meaning might entail an entirely different intellectual approach for one who has a Christian, or more broadly, a religious worldview, than one who does not. A person with a religious worldview would assume that the answers to the fundamental questions in their lives can be pursued (though not necessarily answered) through religion. So a worldview is, in a sense, a framework for understanding the world, and some of the beliefs, attitudes that comprise a worldview are not really conscious.
Indeed a fine answer/respons above!
One could also say that in a spiritual/subconscious or intuitive sense, a 'worldview' is our individual perception of the world as seen/coloured by factors such as our beliefs, background/upbringing, education, experiences in life and so on.
It is a 'cognitive' concept, you see, to do with the subconscious as much as the conscious levels of being/existing.