Super affectionate term used when a straight male has a female best friend: ie a bestie with breasts. More common among men who favor brunch.
Yo dude, you wanna come over on Sunday morning to watch the game? No thanks, my breastie and I wanna put some poached eggs and bloody marys in our mouths.
A strong and complex nonsexual relationship between two or more females that is greater than being BFF. Similar to a bromance.
If Jennifer Aniston and Courteney Cox weren't strait I would swear they were lesbians. I guess they are just breasties.