Traditionally Igbo week consists of four days, which is normally four market days, which are: Eke (eke), Orie (orie), Afo (afo), Nkwo (nkwo).
Every town in Igbo Land has its own market day. For example, Umuaka town might have their market day as Eke, while Akpala town has its own market day as Orie. Amaike town might have their own market day as Afo, and Uloise town has its market day as Nkwo.
Therefore before the supermarkets, malls, shops or shopping centres, I am talking of 1200s - 1900s, if say for example, today is Afo market day, it means everybody including traders from Umuaka, Akpala and Uloise towns will be heading to Amaike town market to sell or buy all they require.
Likewise, if today for an example is Eke market, it means everybody from Amaike, Akpala and Uloise towns will be heading to Umuaka to sell their produce and buy.
To buy and sell would mean that people who produced more yams in their farms may sell or exchange their yams for something else or sell their yams to have money to buy oil or meat in the market.
Likewise, people who grew a lot of vegetables may want to sell them to buy yam, fish or other things. Traditionally, this is how people in Igbo Land used to live in those days, although it still goes on now but not as many people used to rely on them then.
Then rotation of market days - meant that if a person is not too well or strong enough to travel to different markets every day, the person will have to wait for three days when it will be the turn of his or her local market to open, so that he or she can buy or sell.
The markets start normally very early in the morning till midday or so.
Therefore, Igbo market days are Eke, Orie, Afo, Nkwo, which still exist today and used by many traders and others wishing to buy or sell. Sometime people may use market days as a figure of speech - like for example, come to my house after Nkwo market day.