In psychology, any event or situation that makes heightened demands on a person's mental or emotional resources. Stress can be caused by overwork, anxiety about exams, money, or job security, unemployment, bereavement, poor relationships, marriage breakdown, sexual difficulties, poor living or working conditions, and constant exposure to loud noise.
Many changes that are apparently “for the better”, such as being promoted at work, going to a new school, moving to a new house, and getting married, are also a source of stress. Stress can cause, or aggravate, physical illnesses, among them psoriasis, eczema, asthma, stomach and mouth ulcers. Apart from removing the source of stress, acquiring some control over it and learning to relax when possible are the best treatments.

ETYM See Stress (n.).
1. To put stress on; utter with an accent; SYN. accent.
2. To stress, single out as important; SYN. emphasize, punctuate, accent, accentuate.