What is the meaning of the word "cross"?

Definitions:

any affliction that causes great suffering noun
- That is our cross to bear.
in genetics, the act of mixing different species or varieties of animals or plants and thus to produce hybrids noun
- I like to cross orchids in my spare time.
to breed animals or plants using parents of different races and varieties verb
- cross a horse and a donkey
to fold so as to resemble a cross verb
- I crossed my legs.
to meet and pass verb
- the trains crossed
to trace a line through or across verb
- cross your `t'