Netherfront

The most noteworthy altar-cloths were a set given by Alice Chester, the overfront representing our Lord rising out of the Sepulchre, sometimes called our Lord's Pity, with a netherfront and two curtains all "of one work."

Source: wiktionary

To the lowest linen cloth was attached, a band of rich material, that hung over the front of the altar and hid the attachment of the netherfront.

Source: wiktionary

It seems quite possible that the 'greater sorte' of silk pictures in particular were intended to adorn an altar, either as an overfront, a netherfront or even a reredos.

Source: wiktionary