According to http://medical-dictionary.thefreedictionary.com/trigger it's:
"an event that stimulates initiation of a
subsequent event or process."
There is also a really good definition of trigger that you can find here: psychologytoday.com . It has some good thoughts on triggers, though I don't know if I agree on the rest of the article. This is not an endorsement of any kind.
So, basically, a trigger is anything that starts a process. So. . . if an addict always turned to his or her computer after being yelled at by their boss then I suppose being yelled at by their boss would turn into their trigger. Or would it be anger or opposition to authority?
Get the picture, though? An example they give in the article is that hearing a song you used to get high to could be a trigger. It is something that puts them back into their addict mindset.
The first time I heard the term "trigger" in reference to the spouse of an addict, I was confused. What do triggers have to do with the spouses? Aside from "trigger" being a general word that can basically be applied to anything that starts a reaction.
I learned that spouses of addicts can have their own triggers. For example: if an spouse of an addict sees his wife texting, it could cause him to worry and stress because he's wondering who is on the other end of that conversation? Is it him? The other man?
Another example: The spouse of an addict and her husband go to a neighborhood pool party and one of their neighbors is wearing a bikini. As a result the spouse stews the whole night about what is going on in her husband's head. Is he focusing on the neighbor?
I learned that recognizing your triggers can help you work through them.
The other day I read an article in which the poster warned that it might not be a good read for survivors of abusive relationships because it could contain triggers. So in other words things that remind them, things that put them back into that mindset.
So that is what a "Trigger" is.