1: a new style of decorating which embraces one's eclectic, personal treasures by combining them with other items with divergent styles;
2: designed without the conventional rules espoused by decorators, i.e., matching traditional with traditional, coordinating curtains with upholstery fabrics, etc.
This describes a combination of many different individual elements of styles, themes, mediums or inspirations pooled from many sources. It can refer to musical tastes, dress sense, interior design...many things.
She has an ecletic sense of style, today she wears biker boots, pink fishnet stockings, a pencil skirt, a military jacket, a baseball hat, a my little pony t-shirt and a dunlop bag covered in badges from all her favourite bands from ABBA to Kooks