Bandhu (1), Sanskrit for friend connected with bandhan" or ties which are the connections that, according to the Vedas link the outer and the inner worlds. Vedic texts speak, for example, of the 360 bones of the fetus that fuse into the 206 bones of the adult (after the 360 days of the year). Recently, the word has been used in a Song of a Bollywood Feature Film " Cocktail ", Where a Man Calls a girl(Tum hi ho Bandhu)he likes and Rates her as an Angel from the outer world Connected to him. It is used commonly in Hindi in the sense of "friend". Synonyms: "Hindi", it may mean sakha" as in "Twamecha Bandhu, sakha twameva", part of the Krishna stotra, where Lord Krishna is being referred to as friend". In Urdu it takes the meaning of dost.
References:
1. Bhaktivedanta VedaBase: Śrīmad Bhāgavatam 1.14.6, http://vedabase.net/sb/1/14/6/