The Collaborative International Dictionary of English v.0.48:

Dacapo \Da`ca"po\ [It., from [the] head or beginning.] (Mus.)
   From the beginning; a direction to return to, and end with,
   the first strain; -- indicated by the letters D. C. Also, the
   strain so repeated.
   [1913 Webster]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

DACAPO
       ??? [hardware description language] (HDL)


The Free On-line Dictionary of Computing (30 December 2018):

DACAPO

   Broad-range hardware specification language.  "Mixed Level
   Modelling and Simulation of VLSI Systems", F.J. Rammig in
   Logic Design and Simulation, E. Horbst ed, N-H 1986.