The term "condolence" refers to:

The term "condolence" specifically relates to offering sympathy or support to someone who is experiencing grief, typically due to the loss of a loved one. It reflects a recognition and acknowledgment of the pain that another person is feeling, and the gesture is often communicated through words, cards, or actions intended to provide comfort. This understanding of the term aligns clearly with the definition of expressing one’s sorrow or compassion towards someone else's hardships, especially in the context of mourning.

The other options do not correctly capture the meaning of "condolence." Expressions of happiness refer to a positive sentiment that does not relate to sympathy or grief. A form of greeting might convey friendliness or acknowledgment but lacks the depth of emotional support that condolence entails. Lastly, a request for assistance is entirely different as it usually implies seeking help or resources, which does not inherently convey emotional understanding or compassion in response to someone’s loss.