“Holy Ark”, “ark”, meaning more literally “cupboard”, “receptacle”. This is the compartment in the synagogue inside which the Sefer Torah is kept, namely the handwritten scroll of the Pentateuch on parchment.
This is the most precious place in the synagogue, conceived in the image of that Ark of the Covenant, aron ha-berit, which contained the tablets of the law received by Moses on Sinai, and which travelled with the children of Israel until it was finally translated into the Temple.
The aron ha-qodesh is normally placed against the wall of the synagogue that faces east, that is, in the direction of Jerusalem. Often adorned with friezes, the aron ha-qodesh is veiled by an embroidered cloth that hangs in front of it, called a paroket. When the cupboard is opened, as a sign of deference towards the Torah, one stands up.
Source: "Gli ebrei questi sconosciuti" by Elena Loewenthal