Note that this distinction is not always observed; for example, the UK's inheritance tax is a tax on the assets of the deceased, and strictly speaking is therefore an estate tax. For historical reasons, the term death duty is still used colloquially (though not legally) in the UK and some Commonwealth countries.
An understanding of the clear light mind therefore becomes crucial in the context of spiritual endeavor. In general, the mind can be defined as an entity that has the nature of mere experience, that is, clarity and knowing.. It is the knowing nature, or agency, that is called mind, and this is non-material. But within the category of mind there are also gross levels, such as our sensory perceptions, which cannot function or even come into being without depending on physical organs like our senses.
Brain is like the hardware and mind is like the software. But in reality, the difference between brain mind are more complicated than software and hardware. In our culture we sometimes use the words brain and mind interchangeably even though they really do refer to separate, although often overlapping, concepts. The brain is an organ but the mind isn't. The brain is the physical place where the mind resides. It is a vessel in which the electronic impulses that create thought are contained. With the brain you coordinate your moves, your organism, your activities and transmit impulses. But you use the mind to think.