Polyamory, as the old t-shirt says, is wrong.
Polyamory is the practice or lifestyle of loving more than one person with the consent of all parties involved. People who are polyamorous might be involved in a relationship with multiple people, or might be involved in multiple relationships. It's not the same as cheating, because one of the defining features of polyamory is total honesty with all partners.
And it's wrong. Well, the term is, anyway. You see, poly comes from Greek and amory from Latin. So it would be either polyphilia or multiamory.
But that's not the only thing that's wrong, according to Everything You Know About English is Wrong by Bill Brohaugh.
The idea that a dialogue can only be between two people is wrong. The thing is, you've got the word monologue, which is a speech by one person, from the Greek monologus, meaning speaking alone. Dialogue is from the Greek dialogos, meaning conversation, and it's related to the Greek word dialogesthai which comes from the words legein for speak and dia for across. People think since mono refers to one, dia must refer to two. But nope. Across. Who knew.
In computer-ese, it's called dialog, as in dialog box. It's very confusing to keep switching back and forth.
Also, at work, we capitalize the word Support when we're referring to the Customer Support department, and Help when we're referring to our documentation (as in "See the Help for more information"). Now I try to capitalize those words whenever I use them, when I'm using them as proper nouns.