Whenever used in this article, the following words and terms shall have the definition and meaning herein prescribed unless the intention of giving a more limited meaning is disclosed by the context:
"Tax commission" or "department" shall mean the Department of Revenue of the State of Mississippi.
"Commissioner" shall mean the Commissioner of Revenue of the Department of Revenue.
"Person" shall include a natural person, firm, corporation, copartnership, joint venture, association, estate or any other group or combination acting as a unit and the plural as well as the singular thereof.
"Taxpayer" shall mean any person liable for the tax hereunder.
"Sale" or "purchase" shall include the barter or exchange of properties as well as the sale or purchase thereof for money, and every closed transaction by which the title to tangible property passes, either within or without this state, shall constitute a taxable event, whether compensation shall be money or service or some other thing of value.
"Purchase price" or "sales price" shall mean the total amount for which tangible personal property is purchased or sold, valued in money, whether paid in money or merchandise; provided that cash discounts allowed and taken shall not be included.
"Tangible personal property" shall mean tangible goods, wares and merchandise when sold, purchased or delivered within this state.
"Salesman" or "salesmen" shall mean and include any and all persons engaged in the itinerant solicitation and taking of orders for tangible personal property by use of the highways of this state for subsequent delivery to retailers or consumers within this state.