A bachelor pad essentially means a house (pad) in which a bachelor or bachelors (single men) live. It should not be confused with a bachelor apartment, which is a zero bedroom apartment where the main room serves as a bedroom, living room and dining room (and sometimes kitchen).
In the United Kingdom the term bachelor pad usually refers to a flat where a single young man lives alone. Most students in the UK are unable to afford this luxury, and are forced to live with other students, hence the heightened social status attributed to this particular sense of the phrase.
