The rhyme with pres suggests the word is not simply the plural of portice, but a hapax, with a singular form tentatively reconstructed as porticel (in AND¹) or porticet (in TL). However, it is debatable in this context whether the word should be read as a plural. A plural form seems semantically, etymologically (the specific sense, ‘side-chapel’, is already attested in Latin porticus (DMLBS 2355b), the etymon of portice) and grammatically (plural ‘a[s]’ is an editorial correction) unlikely.