Bosom is a Victorian word that you don't hear too often nowadays. It denotes breasts which are not just big but are...expansive. Do Dolly Parton and Jane Mansfield have bosoms? Yes, I think so but I can't say for sure without examining them. A real bosom requires a certain amount of chest area above the boobs. I'm not a bosom fetishist, mind you, I like all kinds of breasts, but like all men I follow any news about this area with keen interest.
The last famous bosom that I know of was owned by Elsa Maxwell, the famous hostess of the 40s and 50s. That's Elsa in the caricature and the cooking ad. Hers was a noble Milt Gross - type bosom. I wonder what she looked like when she was young, something she's definitely not here. When Elsa departed the world she took bosoms with her. No, wait a minute. I forgot about Aunt Bee.