nounplural noun Ds, plural noun D's
1The fourth letter of the alphabet.
- ‘Each half resembles a uppercase letter D, so the two parts of the cyclotron are known as dees.’
- 1.1Denoting the fourth in a set of items, categories, sizes, etc.
- 1.2The fourth-highest category of academic mark.
- 1.3dChess Denoting the fourth file from the left, as viewed from White's side of the board.
- 1.4Denoting the second-lowest-earning socio-economic category for marketing purposes, including semi-skilled and unskilled personnel.
2
(also D)A shape like that of a capital D.- ‘the D-shaped handle’
- 2.1A loop or ring in the shape of a capital D.
- ‘a saddle with stainless steel dees’
- 2.2(in some team sports) the marked semicircular area in front of or surrounding the goal at each end of the pitch or court.
- ‘she completed the scoring in the final five minutes, running into the D and shooting into the bottom right corner’
- 2.3DA semicircle marked on a billiard table in the baulk area, with its diameter part of the baulk line, within which a player must place the cue ball when breaking off or restarting from hand.
3usually DMusic
The second note of the diatonic scale of C major.- 3.1A key based on a scale with D as its keynote.
4The Roman numeral for 500.
Origin
Understood as half of CIƆ, an earlier form of M (= 1,000).
abbreviation
1(in the US) Democrat or Democratic.
- ‘Delaware: breakdown of outgoing Senate: 13 D, 8 R’
2Depth (in the sense of the dimension of an object from front to back)
- ‘H 35 cm × W 50 cm × D 20 cm’
3Chemistry
Dextrorotatory.- ‘D-glucose’
4(with a numeral) dimension(s) or dimensional.
- ‘a 3-D model’
5(in tables of sports results) drawn.
6(on an automatic gear shift) drive.
7Germany (international vehicle registration).
Origin
From German Deutschland.
1Physics
Electric flux density.2Chemistry
The hydrogen isotope deuterium.
abbreviation
1(in genealogies) daughter.
- ‘Henry m. Georgina 1957, 1s 2d’
2Day(s)
- ‘orbital period (Mars): 687.0 d’
3in combination (in units of measurement) deci-.
4(in travel timetables) departs.
- ‘Plymouth d 0721’
5d.Died (used to indicate a date of death)
- ‘Barents, Willem (d.1597)’
6British Penny or pence (of pre-decimal currency)
- ‘£20 10s 6d’
Origin
From Latin denarius ‘penny’.
7Chemistry
Denoting electrons and orbitals possessing two units of angular momentum.- ‘d-electrons’
Origin
Dfrom diffuse, originally applied to lines in atomic spectra.
Mathematics
1Diameter.
- ‘the circumference of a circle is expressed by the formula πd’
2Denoting a small increment in a given variable.
- ‘dy/dx’