Crisis
A crisis may be defined as “1) an internal experience of emotional change and distress, and 2) a social event in which a disastrous event disrupts some essential functions of existing social institutions.” (Barker, 103) Generally, it is any experience that causes distress, either due to natural life changes or outside forces that act upon a person and force change. It is not a negative term, necessarily, depending on how it affects the person who undergoes the crisis state: some come out stronger, and some do not.
Precipitating Event
A precipitating event (or precipitating factor) is anything that disrupts the balance of a person's life and leads to a state of "active crisis" (Kennedy, 389). It could easily be compared to the proverbial "straw that broke the camel's back," in that it is something that may or may not be related to other things that weigh on the person, but it is the thing that causes all the other weight to become unbearable, and it is something whose ability to bring crisis cannot necessarily be anticipated.
Works Cited
Barker, Robert L. The Social Work Dictionary. 5th edition. NASW Press : Washington, DC. 2003
Kennedy, Eugene and Charles, Sara. On Becoming a Counselor: A Basic Guide for Nonprofessional Counselors and Other Helpers. Crossroad Publishing Co. : New York, NY. 2001.