Joshi is a surname used by the Brahmins (caste) in India and Nepal. Joshi is also sometimes spelled as Jyoshi. The name is popularly derived from the Sanskrit word Jyotisha (ज्योतिष, IAST: Jyotiṣa), referring to Vedic Astrology and astronomy; in turn, Jyotisha is derived from Jyotish (light bringer or reflect light like sun). Joshi is a common family name in the Indian states of Andhra Pradesh, Delhi, Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Odisha, Punjab, Rajasthan, Uttarakhand and Uttar Pradesh. In Nepal, it is adopted by two different ethnic groups, the Kumai (Khas) Bahun and the Chatharīya (Kshatriya) Newars.In the Marathi populated Deccan (Chitpavan and Deshastha Brahmans), the last name Joshi is pronounced as ज़ोशी (dental J, closer to Z) as opposed to जोशी in rest of India and Nepal.
Bio from Wikipedia - See more on en.wikipedia.org Text under CC-BY-SA license