What I consider to be my base layer is any underwear or long john items I have. I’ve seen a lot of differing ideas of what the base layer is. Some people define it as the layer that is next to your skin, so if you’re not wearing long underwear under your shirt, then your shirt is your base layer. I have a hard time organizing it like that in my head so I usually just stick to anything traditionally known as underwear is my base layer. That said, I have no qualms about wearing my long johns in a way where they are seen, so I will wear my tops like shirts and whatnot.