Ap is the Vedic Sanskrit term for "water", in Classical Sanskrit occurring only in the plural, (sometimes re-analysed as a thematic singular, ), whence Hindi . The term is from PIE hxap "water" The Indo-Iranian word survives also, as the Persian word for water, Aab, e.g. in Punjab (from "five waters"). In archaic ablauting contractions, the laryngeal of the PIE root remains visible in Vedic Sanskrit, e.g. "against the current", from *.