Literally, "person of
art". A profession with centuries of tradition in
Japan. Most
gaijin either think it means "prostitute" because some actual prostitutes wrongly call themselves that, or they have read
Memoirs of a Geisha, which gives a much better account of the whole thing, but allegedly the woman whose experiences it is actually based on still thinks the author put too great a stress on the sexual aspects.
That the profession has a sexual aspect is undeniable, but at worst, a Geisha is similar to a high-class callgirl, and this is rather optional. It is (or at least used to be) relatively common for Geishas to become mistress to a rich man in order to pay back her Geisha house (see below).
But first and foremost, being a Geisha is about being perfection, in looks, manners and education. Their actual job consists of providing entertainment and creating a pleasant atmosphere at Geisha parties. Nowadays, these parties are extremely exclusive, if not aristocratic events, appropriate for occasions like the sealing of a major business deal between large corporations, because the service of a single Geisha can cost several thousand dollars per evening. This was different in the past, Geisha parties were nothing special, but somewhere along the way, it turned from mainstream entertainment into what it is now.
Geisha trainees start at a very young age (not quite so young nowadays): they enter a Geisha house and are called tamago (egg). They get a very intensive education in classical Japanese poetry, music (especially the koto) and dance, as well as a broad general education (to improve conversational skills). At the age of 17, they can become Maiko, not a full Geisha yet, but allowed to attend the parties and work partially. After they have become full Geisha, they start to pay back the Geisha house for their education and equipment (a good kimono costs a fortune). Geishas who are very successful may earn enough money to start their own Geisha house.