The term 'SIGN UP FOR' can be used to describe a variety of activities. ENROLL, ENTER, APPLY, JOIN, and ENROL are all words that can be used to describe the process of signing up for something. ENROLL is a six letter word that means to register or officially become a member of an organization or program. ENTER is a five letter word that means to take part in a competition or activity. APPLY is a five letter word that means to make a formal request for something, such as a job or a loan. JOIN is a four letter word that means to become a member of a group or organization. ENROL is a five letter word that means to register or officially become a member of an organization or program. All of these words can be used to describe the process of signing up for something.