deciduous

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Falling off or shed at a specific season or stage of growth: deciduous antlers; deciduous leaves; deciduous teeth.
2. adj. Shedding or losing foliage at the end of the growing season: deciduous trees.
3. adj. Not lasting; ephemeral.

Century Dictionary and Cyclopedia

1. Falling or liable to fall, especially after a definite period of time; not perennial or permanent.
2. Specifically— In botany: Falling off at maturity or at the end of the season, as petals, leaves, fruit, etc.: in distinction from fugacious or caducous organs, which fall soon after their appearance, and from persistent or permanent, or, as applied to leaves, from evergreen. Losing the foliage every year: as, deciduous trees.
3. In zoology: Falling off at a certain stage of an animal's existence, as the hair, horns, and teeth of certain animals. Losing certain parts regularly and periodically, or at certain stages or ages: as, a deciduous insect.

Wiktionary

1. adj. biology Describing a part that falls off, or is shed, at a particular time or stage of development.
2. adj. botany Of or pertaining to trees which lose their leaves in winter or the dry season.
3. adj. transitory, ephemeral, not lasting

GNU Webster's 1913

1. adj. (Biol.) Falling off, or subject to fall or be shed, at a certain season, or a certain stage or interval of growth, as leaves (except of evergreens) in autumn, or as parts of animals, such as hair, teeth, antlers, etc.; also, shedding leaves or parts at certain seasons, stages, or intervals

WordNet 3.0

1. adj. (of plants and shrubs) shedding foliage at the end of the growing season
2. adj. (of teeth, antlers, etc.) being shed at the end of a period of growth