You know, this is a place that might actually be able to provide a definitive answer to me.  A brief web search found me asking the same question in 1995.

When I were a wee lad, I was told `dd` was short for `do DEBE`, which, while obviously referencing a well-known movie about a Northern Texas sports team and their most enthusiastic fan, also referred to the mainframe software whose name was an acronym for `Does Everything But Eat` and whose function was to copy data across sources with very different blocking and representation conventions...which is kinda what `dd` does.

Can anyone here confirm or deny that origin for the utility's name?

Adam