Nobody's changing the definition.DON'T ADAPT!! These people (or any people) have no right to take an established word, change it to their own definition. Why bend over to their wants when it is wrong. There is no such thing as "non-binary" and one cannot change their own sex. Those who say otherwise are liars and/or living in their own delusions. They (the correct plural meaning of the word) have no right to make the rest of us join in their delusions.
they
(ðeɪ)
pron.pl. poss. their theirs, obj. them.
1. nominative plural of he, she, and it.
2. people in general: They say he's rich.
3. (used with an indefinite singular antecedent in place of the definite masculine he or the definite feminine she): Whoever is of voting age, whether they are interested in politics or not, should vote.
Consider the example I used a while back:
"Somebody broke into the store. They are stealing the apples."
One person. The correct pronoun is "they".
(Yeah, apples are a pretty stupid thing to steal from a store, but there were previous examples with apples.)