periskopa is the neuter plural definite of periskop.

periskopN

Kven

periskooppiN

Norwegian Bokmål – Kvendict-nob-fkv/src/N_nobfkv.xml:106571Edit on GitHub Suggest

Case	Sg	Pl
Indef	periskop	periskop
Def	periskopet	periskopa