della

Likely from Danish dille, from Latin dēlīrium.

della f (genitive singular dellu, nominative plural dellur)

1. nonsense

   Synonyms: bull, þvaður, þvættingur

2. fad, passionate interest

   Hann er með bíladellu. ― He is extremely interested in and passionate about cars.

   Hann er algjör dellukarl. ― He's the type of guy who becomes passionately interested in various activities and gadgets.

• “della” in the Dictionary of Modern Icelandic (in Icelandic) and ISLEX (in the Nordic languages)

From di +‎ la, ultimately derived from Vulgar Latin dē illa.

della

1. contraction of di la; of the, from the

• dalle

della

1. Obsolete spelling of dela

• d'ella (obsolete)

della f (plural dellas, masculine dello, masculine plural dellos)

1. (obsolete) (contraction of de and ella) of the
   • 1605, Miguel de Cervantes, “Capítulo I”, in El ingenioso hidalgo Don Quijote de la Mancha, Primera parte:

     El resto della concluían sayo de velarte, calzas de velludo para las fiestas, con sus pantuflos de lo mesmo, y los días de entresemana se honraba con su vellorí de lo más fino.

     The rest of it went in a doublet of fine cloth and velvet breeches and shoes to match for holidays, while on week-days he made a brave figure in his best homespun.

• “dello”, in Diccionario de la lengua española, Vigésima tercera edición, Real Academia Española, 2014