Main Entry: in·er·tia

Pronunciation: \in-ˈər-shə, -shē-ə\

Function: noun

1 a : a property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force b : an analogous property of other physical quantities (as electricity)
2 : lack of activity or movement—used especially of the uterus in labor when its contractions are weak or irregular