Bohemian- "Boho" for short refers to an ethnic look that combines clothing and accessories similar to those worn by native people from around the world. To me, it indicates more of an attitude than a definite style, since Bohemian can be used to describe many different looks.
Think back to the late 1960's to early 1970's era of flower children and hippies. Boho jewelry was worn a lot during this time period - with layered clothing and accessories made from natural materials and big, bold chunky styles.
Throughout history, bohemian style jewelry has always been admired for its statement, weight of the pieces and the colors used. The jewelry is very organic; it uses a lot of wood and genuine stones as some of the prominent materials. Ivory and bone was also a material often used. Many of the styles can be considered "plus sized" - not because they are to be worn by larger women, but because the jewelry itself becomes the fashion statement because of the size.
Eastern Europe is credited with being the origination of Bohemian jewelry, since it these countries are normally associated with gypsies and others in nomadic populations. It is associated with free thinking, organic, individuals. This is the same reason we tend to think of Bohemian jewelry and hippies. The two went hand in hand during the 1970s. Self expression is the key to the mood and trend in Bohemian jewelry.
The Bohemian fashion trend is currently experiencing a rebirth, with many popular Hollywood stars now sporting this style of jewelry. Here are a few examples: