diagonal (something arranged diagonally or obliquely) / diagonal (diagonal line or plane)

diabetes (a group of metabolic diseases)

Superseded spelling of dialetal. (Superseded in Brazil by the 1943 spelling reform and by the Portuguese Language Orthographic Agreement of 1990 elsewhere. Still used in countries where the agreement hasn’t come into effect.)

(Roman mythology) Diana (Roman goddess)

diamond

(linear algebra) main diagonal (the elements of a matrix where i = j)

diabetes mellitus (medical disorder)

(rare) zebra finch (Taeniopygia guttata, a bird)

(chemistry) arbor Dianae (an arborescent precipitation of silver)

A village and municipality of Paraná, Brazil