The reason Speedos are stigmatised

[Dooley67]

OK guys, I need some clarification here. STS rightfully said that Speedo is a brand, not a type of swimsuit. I will often refer to a brief suit as a speedo or as a bikini. So, since Speedo is a brand, how do we differentiate between a "speedo type" suit and a bikini? Is it the size of the side seam or whether the suit creates the "v" shape or low cut straight line that Turbofan talked about?

D67