Kheer is derived from the Sanskrit word क्षीर "Ksheer" meaning milk. Alternate name is again derived from the Sanskrit word पयस "payas" meaning milk and paayas means milk derivative. In Bengali kheer gets the name Payesh and in South India it is Payasam/Paayasa.
One of the oldest recipes surviving which is mentioned even in ancient texts. One of the ancient texts describes a Goddess in Kashmir as Paayasannapriya.
Did you know that the English rice pudding is believed to be inspired by our own kheer?