Carrie Fisher and Debbie Reynolds' deep mother/daughter bond is now memorialized with their massive combined headstone ... which was unveiled over the weekend.

It's minimal on text -- etched only with their names and lifespans underneath a statue of 2 people embracing. Debbie and Carrie were laid to rest alongside one another in January at Hollywood's Forest Lawn Memorial Park.

Carrie was cremated but some of her ashes were placed in an urn shaped like a giant Prozac pill next to her mother.