Noun

(uncountable) Inadequacy or incompleteness.

* {{quote-book, year=1963, author=(Margery Allingham), title=(The China Governess)

, chapter=17 citation , passage=The face which emerged was not reassuring. […]. He was not a mongol but there was a deficiency of a sort there, and it was not made more pretty by a latter-day hair cut which involved eccentrically long elf-locks and oiled black curls.}}

(countable) An insufficiency, especially of something essential to health.

* {{quote-magazine, date=2013-08-31, volume=408, issue=8851, magazine=(The Economist)

, title= Promotion and self-promotion , passage=One of academia’s deficiencies is that, though its lecture halls and graduate schools are replete with women, its higher echelons are not. Often, this is seen as a phenomenon specific to the sciences. … In fact, the disparity applies to the whole grove. Another report from 2006, by the American Association of University Professors, found the same ratio in the faculties of arts, humanities and social science, too.}}

(geometry) The amount by which the number of double points on a curve is short of the maximum for curves of the same degree.

(geometry) The codimension of a linear system in the corresponding complete linear system.

Noun

(uncountable) The process of developing; growth, directed change.

* {{quote-magazine, date=2013-07-19, author= Ian Sample

, volume=189, issue=6, page=34, magazine=(The Guardian Weekly) , title= Irregular bedtimes may affect children's brains , passage=Irregular bedtimes may disrupt healthy brain development in young children, according to a study of intelligence and sleeping habits.  ¶ Going to bed at a different time each night affected girls more than boys, but both fared worse on mental tasks than children who had a set bedtime, researchers found.}}

(uncountable, biology) The process by which a mature multicellular organism or part of an organism is produced by the addition of new cells.

*

Of more significance in the nature of branch development ; in the Jubulaceae, as in the Porellaceae, branches are acroscopic and normally replace a ventral leaf lobe.

(countable) Something which has developed.

(real estate, countable) A project consisting of one or more commercial or residential buildings, real estate development.

(real estate, uncountable) The building of a real estate development.

(uncountable) The application of new ideas to practical problems (''cf. research).

(chess, uncountable) The active placement of the pieces, or the process of achieving it.

(music) The second section of a piece of music in sonata form.