An anna (or ānna) was a currency unit formerly used in British India, equal to 1⁄16 of a rupee.
The term anna is frequently used to express a fraction of 1⁄16.
[2] With the rupee having been valued to 1s 6d[3] and weighing 180 grains as a 916.66 fine silver coin,[4] the anna was equivalent to 9/8 d (one penny and half a farthing).
Hence the 2 anna silver coins were of low weight (22.5 grains = 1.46 g).
Anna-denominated postage stamps were issued during the British Raj by the government of British India as well as by several princely states, and after independence until decimalisation of the currency by India and Pakistan.