The first person, or someone in general that you are attracted to, who made you question or change your sexuality. Most commonly used by Bisexual individuals to suggest that they like someone, either to the person that they like, or to someone who is unknowing of that person's sexuality.
Colby: Why are you staring at Diamond like that?
Sandi: Oh, she's my purple...
Colby: Wait. You like her? Does that mean you're Bisexual?
Sandi: Yes I am, but please don't tell anybody and don't tell her, I haven't come out to her yet. Promise?
Colby: I promise.
when your dealer says your weed is "granddaddy purple kush," he means i'm an idiot and don't really know what type of weed it is. There is no such thing. It could be Granddaddy purple or purple kush, but not both.
"yo i want some granddaddy purple kush" "what the he** is that?"