What are the legal definitions of a straw sale or a straw purchase especially as it applies to firearms?

Straw sales and purchases of firearms are referred to as the straw man doctrine. A straw purchase occurs when one person (the straw purchaser) buys a firearm from a licensed firearms dealer on behalf of someone else (the actual buyer) and misrepresents himself to be the purchaser. This most frequently happens when a person who is not eligible to lawfully possess or purchase a gun, uses a person who is eligible to possess and own a weapon, as an intermediary or agent to buy the gun for him. Federal law provides that: it shall be unlawful ... for any person in connection with the acquisition ... of any firearm ... from a ... licensed dealer ... knowingly to make any false or fictitious oral or written statement or to furnish or exhibit any false, fictitious, or misrepresented identification, intended or likely to deceive such ... dealer ... with respect to any fact material to the lawfulness of the sale or other disposition of such firearm. When you buy a gun from a licensed firearms dealer, you are required to fill out a Federal Form 4473, which specifically asks, Are you the actual buyer of the firearm indicated on this form? The form explains that Any individual who is not buying the firearm for himself or herself or as a gift, but who completes the form, violates the law. It defines a straw purchase as occurring when the actual buyer uses another person (the straw purchaser) to execute an ATF Form 4473 purporting to show that the straw purchaser is the actual buyer. Straw purchases also place the straw purchaser and the actual buyer in violation of law. The Federal firearms laws thus require that the individual filling out this form must be buying the firearm for himself or herself or as a gift. A firearms dealer can be liable for making a straw sale of a firearm. Federal law provides: It shall be unlawful for any . . . licensed dealer . . . to sell or deliver any firearm to any person in any State where the purchase or possession by such person of such firearm would be in violation of any State law . . . unless the licensee knows or has reasonable cause to believe that the purchase or possession would not be in violation of such State law.