denne.

From Old Danish thænnæ, Old Norse þenna, accusative of sjá. A derivation with a deictic suffix from the demonstrative den, from accusative Old Norse þann, accusative of sá. The neuter form dette goes back to Old Danish thættæ, Old Norse þetta, derived from the demonstrative det, from Old Danish thæt, Old Norse þat. The plural disse goes back to Old Danish thæssæ, Old Norse þessa, derived from de, from Old Danish the, Old Norse þá, but with a different suffix, which is also used in the singular in the Runic Old Danish form ᚦᚬᚾᛋᛁ (þąnnsi). The s-suffix also occurs in the corresponding West Germanic pronouns, cf. English this and German dieser.