For the several senses of this feminine noun see LSJ s.v.
Same entry in the Synagoge and in Photius, Lexicon pi777 Theodoridis. Hesychius pi1888 has the first gloss, followed by e)/nduma "garment". The second gloss e)pagwgh/ is more problematic: it is not obvious where its meaning (cf. epsilon 1921, epsilon 1922, epsilon 1923) is intended to overlap with that of peristolh/.
The headword itself, in any event, is taken to be quoted from Exodus 33.6 LXX (accusative case there).