Definify.com

Webster 1913 Edition

Noun.

The quality or state of being deciduous.

Noun.

The quality of falling once a year.

DEC'IGRAM, n. A French weight of one tenth of a gram.

DE'CIL, n. An aspect or position of two planets, when they are distant from each other a tenth part of the zodiac.

DEC'ILITER, n. A French measure of capacity equal to one tenth of a liter.

deciduousness ‎(uncountable)

The state or condition of being deciduous; the quality of trees which lose their leaves in winter or the dry season.
- 2010, Geoff Williams & Paul Adam, The Flowering of Australia's Rainforests, page 59
  Worldwide, foliage deciduousness in angiosperms is believed to have arisen in tropical species as a response to periodic drought.

state or condition of being deciduous