Community-supported agriculture (CSA) is a food production and distribution system that directly connects farmers and consumers. In short: people buy "shares" of a farm's harvest in advance and then receive a portion of the crops as they're harvested.
The term "CSA" is also used to refer to an individual farm's CSA program.
Farmers earn important early-season capital and have a guaranteed market for their produce. Barring a disastrous harvest, consumers enjoy overall lower food costs, field-fresh produce, and greater access to high-demand fruits and vegetables like long-stem strawberries and heirloom tomatoes.
Some CSAs offer more than fruits and vegetables. Eggs, honey, flowers, and even poultry and other meats can be part of a vibrant CSA program. Some farms keep the magic going post-harvest by offering members jams, pickles, or other preserves they've made during the peak of harvest.
Most CSAs require an annual or quarterly buy-in and provide weekly deliveries or pick-ups, but some well-established programs offer monthly or even weekly "memberships." Many CSAs also offer farm visits, u-pick days, and other special events for members.