Systems Biology Word of the Week

hys‧ter‧e‧sis  /ˌhɪstəˈrisɪs/ Pronunciation Key - Show Spelled Pronunciation[his-tuh-ree-sis]
–noun Physics.

2.the phenomenon exhibited by a system, often a ferromagnetic or imperfectly elastic material, in which the reaction of the system to changes is dependent upon its past reactions to change.

ie Lactose utilization switching in E. coli is hysteretic due to the regulatory architecture of the Lac operon.

So amazingly obvious, yet so confusing.