Definitions for "Hair shaft"
Refers to hair portion above the skin surface. But in common usage, often refers to any portion of the hair including that which is below the skin surface.
dead part of a hair that pokes out through the skin
That part of the hair that we see above the scalp.
Filament projecting from the epidermis that provides protection and warmth (Hair).
The protein material twisted into a very fine rope-like arrangement that is considered as "hair"