this means~; because~; that is to say
Explains a term by defining it, or gives a reason for a statement.
というのは is used in two main ways. First, it introduces a definition or explanation of a term that was just mentioned. You state the topic, add というのは, and then explain what it means. This is common in casual conversation and writing. Second, it can introduce a reason or cause for something that was said before, similar to 'because'. In this case, the sentence before というのは states a fact or situation, and the part after gives the reason or background.