A hechsher (Hebrew: הכשר‎) is a rabbinic seal of approval that certifies that a product conforms to Jewish dietary law. The word hechsher is derived from the Hebrew root meaning fit, proper or correct. A hechsher may be stamped on food products, indicating that the product has been prepared in accordance with kosher dietary laws.
Hechshers are usually placed on packaged foods, such as cereals, crackers and canned goods. They may also appear on meat, poultry and fish products. Hechshers may be issued by rabbinical organizations or individual rabbis.
The most well-known hechsher in the United States is the OU (Orthodox Union) symbol. Other common symbols include the K (for Kosher), MK (for Mehadrin Kosher) and OK (for Orthodox Kosher).