They are so mentioned because of the relief-like trained cross in the center as symbol of the livetree.
'Khach' - cross and 'Qar' are called - stone. These stone-cutters occur only in Armenia.
The
Khachqars did not only serve as grave places, it also for honours
of all-possible events was set up. In Armenia are some thousands of
these steinplatten, but none resembles the other one. Each
stone-cutter put his fantasy into the ornamentation decoration,
enriched him by plastic items. The size of the flagstones varies
between some dozen of centimeters up to some meters. These small
memorial places manufacture the best stone-cutters of medieval
Armenia.