Accidentally, the expression work (ing)-from-home has many synonyms: work (ing)-at-home, home-based, telecommute (ing), telework (ing) (in British English and Europe in general), e-work and e-commute(ing) (if related to computing jobs) and you will even find the shorts: WAH and WFH.
Work-from-home indicates a way of working, not a job in itself (obvious, I know but...) and means working while you are - as the word says - AT HOME.
According to the job, you may be sitting in front of a computer and/or a traditional telephone connected to a land-line or in a studio with tools you need to use (a sewing machine, watercolors, yarns, i.e. if you get a crafty job).
You will be able to have a coffee, a chat with the neighbour and lunch breaks with the same pace which is tolerated into your office.
They are obviously not jobs where you can take a nap, babysit, play with your cat, walk your dog, watch TV or shop during working hours.
But even if it's not about having great fun, you do avoid commuting which might be stressful and extremely time consuming for some. It's also great when you need to receive a plumber or electrician at your place or need to run errands which need to occur during office hours (if you have an appointment with someone at the city hall, etc.).
Working from home is mainly domain of self-employment especially in recession times when professionals cannot afford renting offices any longer.
As a matter of fact, employment is rarely 100% work-from-home type and even more seldom employers hire directly work-from home workforce (but this is not impossible as I will show you) or if you live very far form the company or in another country.
And I stop here: I wont go into explaining advantages and disadvantages for you and the society, if you are suited/not, tips & tricks of working from home, how to start a home based business also because there are tons of books and websites out there which explain all the above and others much better than me (or worse, uhm...)
Any query, please do not hesitate to comment this post.