WordNet sense 1 (in accordance with fixed order or procedure or principle):

regular

WordNet sense 2 (always the same; showing a single form or character in all occurrences):

unvarying

WordNet sense 3 (the same throughout in structure or composition):

consistent

WordNet sense 4 (all of the same or similar kind or nature):

homogeneous, homogenous

WordNet sense 5 (not differentiated):

undifferentiated