1) Cemetery ceremony 2) Presentation 1) Debut 2) Disclosure 
It is customary for the memorial stone to be unveiled during a ceremony held after the Kaddish period (11 months for parents and 30 days for other close relatives) is over, but no later than one year after the death.
[n] - putting on display for the first time
noun putting on display for the first time; `he attended the unveiling of the statue`
Dedication of the grave marker.
a ceremony in which a statue or monument is presented or displayed for the first time by removing its covering. · an act or instance of presenting, displaying, or revealing, esp. for the first time: the unveiling of a new play.