1. a wooden structure consisting of an upright post with a transverse piece
2. marking consisting of crossing lines
3. a cross as an emblem of Christianity; used in heraldry
4. any affliction that causes great suffering;
"that is his cross to bear"
"he bears his afflictions like a crown of thorns"
5. an organism that is the offspring of genetically dissimilar parents or stock; especially offspring produced by breeding plants or animals of different varieties or breeds or species;
"a mule is a cross between a horse and a donkey"
6. (genetics) the act of mixing different species or varieties of animals or plants and thus to produce hybrids