The Adelphi was a set of buildings in London situated between the Strand and the Thames. Dickens used to walk around the Adelphi buildings as a child. These were close to the Adelphi Theatre, which took its name from them.
The name comes from the Greek word for brothers: the Adelphi was constructed (1768-1772) by brothers John, William, James and Robert Adam.
The original Adelphi buildings were demolished and replaced during the 1930s.