The act of sorrowing or expressing grief; lamentation; sorrow.

Garb, drapery, or emblems indicative of grief, esp. clothing or a badge of somber black.

Grieving; sorrowing; lamenting.

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.

time during which we grieve for the dead

Behavior of the bereaved and the community after a death, including culturally accepted customs and rituals. (618)

the actions or feelings of one who feels or expresses sorrow; specifically, the expression of grief at someone's death.

state of sorrow over the death or departure of a loved one

the passionate and demonstrative activity of expressing grief

sorrowful through loss or deprivation; "bereft of hope"

Process following loss of a loved one in which the person grieves the loss until acceptance is achieved.

the period of time following a loss. Similar to grief and bereavement, a loss may be of a loved one, or loss of an ideal (divorce, job, home, etc.). Mourning may be short or very long and may relate to cultural and religious customs.

Mourning is in the simplest sense synonymous with grief over the death of someone.