concern >> /kənˈsərn/
Definition: [transitive verb] Relate to; be about.
Example: the story concerns a friend of mine
Definition: [transitive verb] Worry (someone); make anxious.
Example: the roof of the barn concerns me because eventually it will fall in
Definition: [noun] Anxiety; worry.
Example: such unsatisfactory work gives cause for concern
Definition: [noun] A matter of interest or importance to someone.
Example: oil reserves are the concern of the Energy Department
Definition: [noun] A business; a firm.
Example: a small, debt-ridden concern
Definition: [noun] A complicated or awkward object or structure.