Experts speak of hair breakage or trichoclasis when hair becomes brittle beyond a normal level. They can break off directly at the hairline or in the lengths. This happens because the individual hairs become rougher and finer over time due to various influences.
The structure becomes weak and breaks. Hair breakage is not to be confused with split ends. With a split end, only the ends of the hair strand are brittle and lackluster. These then begin to splinter after some time.