In Things Fall Apart, the Igbo use epithets which show one's status in the tribe. Among them are:
agadi-nwayi: old woman
agbala: woman; also used of a man who has taken no title
efulefu: worthless man
So, the hierarchy is set up for men, obviously. Men are judged by the accumulation of titles and worth (number of children, wives, cowries, heads). A man who does not have any children, wives, cowries, or heads is simply "worthless," but a man who takes no titles is considered beyond worthless, so weak that he is not a man at all; instead, he is a woman.
Women are not judged by the titles or worth. They must attach themselves to a man in order to attain status. Then, they are given a number: first wife, second wife, third wife--a chain of command. Their status is only secured by marriage. Within marriage, their goal is to provide male children.
Women are also given status if they have survived to be old. With high mortality rates for children and mothers, an old woman would be given respect for her contribution to the tribe in terms of fertility and matriarchy (having and raising many healthy children).
More, women are only give supreme status if they have some kind of religious or supernatural power, like Chielo, the priestess of Agbala, or powerful war medicine, agadi-nwayi, a magic used by the spirit of an old woman with one leg to achieve peace instead of war. Many surrounding villages fear the tribe because their priestess and medicine men are so powerful.