The letter “D” corresponds to the Semitic daleth and Greek delta (Δ). “D” is also the Roman numeral for 500. The form (D) is thought to derive from an early pictograph, possibly Egyptian, indicating the folding door of a tent. Later “D” got its more rounded shape, with which we are familiar, from the Chalcidian alphabet, which the Latins may have borrowed for their alphabet (https://www.britannica.com/topic/D-letter). Words beginning with “D”, numero quattro in the English alphabetical order, are an eclectic lot. They can be delightful, decadent or distasteful. Here’s a brief sampler of logophile-friendly “D” words for serious verbivores. 
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
(word) Dacnomania
(meaning) a compulsive urge to bite
(derivation) Gk dáknō (“bite”) + -mania 🦷
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dactylogram
fingerprint
Gk Daktylos (“finger”) + –gramma (“that which is written/drawn”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Daedalist
aviator; pilot
Gk from Didalos, L Daedalus (“skilfully wrought”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dapifer
one who brings meat to the table (ie, a servant)
origin unknown 🍖
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Defenestration
throw someone through a window; remove or dismiss someone from a position of authority
L de “down from” + –fenestra (“window”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Deimatic
pattern of behaviour of a bluffing character (zool)
Gk deimatóo (“to frighten”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Deipnosophist
learned amateur
Gk deipnon (“dinner”) + –sophistēs (“knowledgeable in the arts” (from Athenaeus’‘Deipnosophistaí’)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Deltiologist
someone who collects and studies postcards [Gk. deltion (“writing tablet”) + -ist]
Deltiologist (image: emaniuz-collection.blogspot.com)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Depontification
throw someone off a bridge
L de + –pons (“bridge), following pattern of defenestration
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Didascalar
Didactic; pertaining to teaching
origin unknown
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Diddicoy
scrap dealer; Brit: group of caravan-dwelling travellers who adopt a Gypsy-like lifestyle
origin unknown
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Diestrus
a period of sexual inactivity
New L dia + -estrus from Gk Oistros (“gadfly”, “sting”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Digladiator
swordfighter
origin unknown
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dithyrambic
wildly irregular in form
Gk dithyrambos (unknown, pre-Hellenic?)
Diversiloquent
able to speak on different topics; in different ways
L. diversi (“diversus”) + –loquēns (“to speak”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Docent
an academic immediately below the professorial rank; a voluntary guide at a museum, zoo or art gallery
L docēns (“to teach”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Doctiloquent
speaking learnedly
L from doceō (“I teach”) +-loquēns (“to speak”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Domatologist
professional housekeeper
origin unknown
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dontopedology
science of putting your foot in your mouth
Gk odoús (“tooth”) + –pes (“foot”) + –logos (“word”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Douanier
customs official
Fr, origin unknown
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Doulocracy
rule by slaves
Gk doûlos (“servant”, “slave”) + –kratéō (“rule)
Doulocracy: Spartacus, slave army leader
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dragoman
interpreter, translator or guide
Gk dragumanus from Arab targuman (“interpreter”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dulciloquent
speaking in a sweet, pleasant and agreeable way
L. dulcis (“sweet”) + -loquēns (“to speak”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Durative
describing an action that is continuing, incomplete; transforming
L. durare (“to harden”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dysania
Difficult to wake up in the morning
origin unknown
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dyschromatopic
colour-blind
Gk dys (“bad”) + -chroma (“colour”) + -ops (“eye”)
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dysphemism
using an offensive word in the place of an inoffensive one
Gk dys (“bad”) + –pheme “speech”,
⍔⌼⌼⌼⌼⌼⌼⌼⌼⍠⌼⌼⌼⌼⌼⌼⌼⌼⍔
Dystelology
doctrine of purposelessness
Gk dys (“bad”) + –télos (“end”, “purpose”, “goal”) + –logos
⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎⚗︎
