Forty-five and Six-gun

Forty-five noun - A .45-caliber pistol.

Six-gun and forty-five are semantically related. In some cases you can use "Six-gun" instead a noun phrase "Forty-five".

Six-gun noun - A pistol with a revolving cylinder (usually having six chambers for bullets).

Forty-five and six-gun are semantically related. You can use "Forty-five" instead a noun phrase "Six-gun".