From The Collaborative International Dictionary of English v.0.48 :
Mourning \Mourn"ing\, a.
1. Grieving; sorrowing; lamenting.
[1913 Webster]
2. Employed to express sorrow or grief; worn or used as
appropriate to the condition of one bereaved or sorrowing;
as, mourning garments; a mourning ring; a mourning pin,
and the like.
[1913 Webster]
Mourning bride (Bot.), a garden flower ({Scabiosa
atropurpurea) with dark purple or crimson flowers in
flattened heads.
Mourning+dove+(Zool.),+a+wild+dove+({Zenaidura+macroura">Mourning dove (Zool.), a wild dove ({Zenaidura macroura)
found throughout the United States; -- so named from its
plaintive note. Called also Carolina dove. See Illust.
under Dove.
Mourning warbler (Zool.), an American ground warbler
({Geothlypis Philadelphia). The male has the head, neck,
and chest, deep ash-gray, mixed with black on the throat
and chest; other lower parts are pure yellow.
[1913 Webster]