One is a pronoun in the English language. It is an indefinite pronoun. For purposes of verb agreement it is a third-person singular pronoun, although it is sometimes used with first- or second-person reference. Occasionally it is called an impersonal pronoun. It is more or less equivalent to the Scotch "a body," the French pronoun on, the German/Scandinavian man, and the Spanish uno. It has the possessive form one's and the reflexive form oneself. The pronoun one has quite formal connotations, and is frequently avoided by the vulgar in favour of more colloquial alternatives such as the generic you.
Today is Diana's birthday. She is pictured above and also in the second of the group photographs below where she is enjoying a meal at our home in the company of the Hungarian poet and journalist, Thomas Land, Sarah and me. She sadly passed away on 16 December 2003. Fr Hubert Condron and I conducted her funeral exactly one month later in the chapel at Islington & St Pancras Cemetery. Panis Angelicus was the only piece of funeral music requested by her. As the coffin slowly moved from view this is what played (click on images). The irony was not lost on me. More than anyone I have known, she adored music.
Diana seated alongside my mother on 8 August 1987 (below).