CSA stands for Community Supported Agriculture

"Many farms offer produce subscriptions, where buyers receive a weekly or monthly basket of produce, flowers, fruits, eggs, milk, coffee, or any sort of different farm products.

A CSA, (for Community Supported Agriculture) is a way for the food buying public to create a relationship with a farm and to receive a weekly basket of produce. By making a financial commitment to a farm, people become "members" (or "shareholders," or "subscribers") of the CSA. Most CSA farmers prefer that members pay for the season up-front, but some farmers will accept weekly or monthly payments. Some CSAs also require that members work a small number of hours on the farm during the growing season.

A CSA season typically runs from late spring through early fall. The number of CSAs in the United States was estimated at 50 in 1990, and has since grown to over 1000."

        - taken from the Local Harvest site where you can find lots of information about CSAs and where to find one near you!