First, thank you for asking. This is something I feel is important!
Second, to those who wonder where this question came from, a while back, I reblogged this, and added the comment about squicks not being the same as triggers.
So what, you ask, is a squick?
A squick is an old fandom term for something that makes you supremely uncomfortable and you absolutely do not want to read it. It can be a trope, a ship, a concept, or just an event that happens within a fic or in canon. For me, abused animals are a definite squick. I don’t like it, and will generally avoid reading any graphic descriptions of such. (That includes tumblr gif sets and such too, people! Tag that shit, will you? Even if it has a happy ending.) Another deep, deep squick of mine is infant age play. Don’t like it, don’t get it, don’t want to think about it.
Now, neither of these things are dangerous to my mental or emotional state. I have never experienced either in my life, and they do not bring about any sort of PTSD, dissociation, or spiral of depression, anxiety, etc. They are simply things I prefer not to think about in my daily life, or read about in my escapist hobbies. Therefore, they are not triggers. Triggers are very real, very bad things for some people, and to label things we choose not to read because we find it disturbing or gross or weird is to diminish the very real danger of actual triggers.
I love the term squick. It perfectly describes the concept without assigning any negativity to the thing you dislike, or to people who do like the thing you dislike. It is something you personally do not care for and wish to avoid, simple as that.