A dress is a type of clothing that women wear:
Dressed (adj.) / Get dressed (v.)
These words can be used with both men AND women.
“Get dressed” means to put on your clothes (the opposite is “get undressed”) and “dressed” can be used to describe what someone is wearing:
Dress up (v.)
“Dress up” means to wear clothing that is special; clothing that is nicer than your regular everyday clothes:
You can also use “dress up” + “as” for costumes: