The word paisa is from Hindi & Urdu paisā, a quarter-anna coin, ultimately from Sanskrit term padāṁśa meaning 'quarter part', from pada 'foot or quarter' and aṁśa 'part'.
Until the 1950s in India and Pakistan (and before 1947 in British India), the paisa was equivalent to 3 pies, ¼ of an anna, or 1⁄64 of a rupee. After the transition from a non-decimal currency to a decimal currency, the paisa equaled 1⁄100 of a rupee and was known as a naya paisa ("new paisa") for a few years to distinguish it from the old paisa that was 1⁄64 of a rupee.
In Hindi, Afghan Persian, and other languages, the word paisa often means money or cash. Medieval trade routes that spanned the Arabian Sea between India, the Arab regions and East Africa spread the usage of Indian and Arabic currency terms across these areas. The word pesa as a reference to money in East African languages such as Swahili dates from that period. An example of this usage is the modern day Kenyan mobile-phone based money transfer service M-Pesa (which stands for mobile pesa or mobile money)