A hechsher is a stamp, symbol or label denoting that a product is kosher. It comes from the word kasher, meaning fitting, right, pleasing, and, in matters of food, kosher.
There is a plethora of hechsherim available: K's in triangles, K's in circles, a U in a circle that is one of the best-known kosher logos, from the Orthodox Union in the United States. In the UK we have our very own KLBD symbol from the London Beth Din.
Traditionally, hechsherim have marked that an object is kosher according to the plain requirements of halachah. But the situation looks as if it is about to get more complicated. Kosher certification was a reliable guarantee that meat had been produced in a humane way. In an age of industrial food production, many doubt whether this is still the case.
In the US, a Conservative body wants to introduce a "hechsher tzedek" that takes into account whether animals are raised and killed humanely and workers are treated properly. An Orthodox organisation in New York, Uri V'tzedek, is introducing a hechsher for kosher restaurants which is based on similar criteria.
But others question whether new hechsherim are necessary. One issue at the core of this debate is whether kashrut is about adherence to a system of God-given laws that we cannot ultimately understand, or whether the laws are also meant to reflect values that the kashrut system needs to lives up to.