Something like perfume
or eau de Cologne
, but less concentrated. Not as sinfully expensive as the undiluted stuff, it's something women (and some men) can afford to splash on a little of every day just to enhance their overall aroma
Eau de toilette is a French term which translates, literally, to "toilet water". But it's not as gross as it sounds at first blush; it doesn't refer to what your dog drinks. Recall that "toilet" has a range of meanings, the more general referring to personal hygiene, or basically what people to to themselves in the morning to make themselves presentable.
In the Renaissance, people believed in courtly manners, courtesy and not offending one's neighbors with offensive body odours. However, the accepted means to this end was to douse oneself in - you guessed it - Eau de toilette.
Nowadays, people have taken to taking showers, and science has blessed us with deodorant. Modern English has pretty much substituted "bathroom" for "toilet", so a more apropos translation might be "bathroom water".