It seems to me that both words are interchangeable, I can mourn or grieve the death of a loved one for weeks, months or years. And both terms mean to feel deep sorrow for the loss of someone dear. According to Oxford and Macmillan, to mourn is to feel and manifest sadness in public whereas to grieve is to only feel sadness. Other dictionary definitions do not make this distinction. However, if we look at Oxford's example of usage: “he was mourned for years”, it is nevertheless ambiguous. Did family and friends attend a memorial service every year (public manifestation)? Or did they simply reminisced whenever they met up (in private; i.e. among friends and relatives)? Would one use grieved if it was the latter, or are the two interchangeable?
mourn
Oxford Dictionaries says:
- Feel or show sorrow for the death of (someone), typically by following conventions such as the wearing of black clothes:
He was lost in battle to his only enemy, and he was mourned for years after his death by the people who had grown to love him.
The Free Dictionary lists the following three definitions;
The American Heritage Dictionary
- To feel or express grief or sorrow. See Synonyms at grieve
Collins English Dictionary
- to feel or express sadness for the death or loss of (someone or something)
Random House Kernerman Webster's College Dictionary
- to feel or express sorrow or grief.
Longman Dictionary of Contemporary English
- to feel very sad and to miss someone after they have died [= grieve for]:
mourn somebody's death/loss/passing
She still mourns the death of her husband.
Macmillan Dictionary
- to feel extremely sad because someone has died, and to express this in public
mourn for: He still mourns for his brother.
grieve
- Feel intense sorrow:
Oxford Dictionaries
The Free Dictionary contains the following three definitions:
- To cause to be sorrowful; distress:
- To mourn or sorrow for
AHD
- to feel or cause to feel great sorrow or distress, esp at the death of someone
CED
- to feel grief or great sorrow.
RHKWCD
- [intransitive and transitive] to feel extremely sad, especially because someone you love has died
grieve over/for
- He died, and every day since then I have grieved for him.
- People need time to grieve after the death of a loved one.
- She grieved the loss of her only son.
LDOCE
[INTRANSITIVE/TRANSITIVE] to feel extremely sad because someone has died
- I never had time to grieve properly.
- He’s still grieving for his wife.
- Millions of people are grieving over his death.
MD
According to a blogger called Jade, there is a significant difference between the two terms [emphasis mine].
While grief is the emotional reaction/response to loss, mourning is the process one undertakes to deal with the void that is now left. Mourning is the process of acclimating to living a life without this special someone or something. It is period of adapting to the changes created by this loss.
Source: grief and mourning.com
The following excerpt seems to confirm this difference, grief is the emotional response but mourning is how we process the death of a loved one
Grief is the natural psychological, behavioral, social, and physical response which helps the mourner recognize the loss and get ready for the larger and often longer experience of mourning. As Therese A. Rando says, “Grief is actually the beginning part of mourning.” Source: The Difference Between Grief and Mourning
Q: What is the difference in meaning between the following?
- People need time to grieve after the death of a loved one
- People need time to mourn after the death of a loved one
- She still mourns the death of her husband.
- She still grieves the death of her husband.
Related: What is the expression for the process of getting over the loss of a loved person?