A person with bands of gray hair - usually at the temples. Gray-Bar's can be of any age, but they are typically in their 40's or older and usually they are men. However, there are progressive women adopting the Gray-Bar look.
Typically, Gray-Bar's have a lot of experience and may be looked down upon by the Gen Y and Millennial crowd. They don't know everything, but their experience should count for something. Just because they are "old" doesn't mean they don't know anything and that they cannot learn anything new. They can!
Man, that meeting was filled with Gray-Bar's.
I can't believe that Gray-Bar was talking about Twitter.