To take active responsibility for a group or process, especially within an organization.
To remain present in a retail business, in order to maintain the security of the premises and to serve customers.
To follow or obey the custom, practice, or rules (especially of a religion).
To take note of and celebrate (a holiday or similar occurrence); to follow (a type of time or calendar reckoning).
To notice or view, especially carefully or with attention to detail.
To comment on something; to make an observation.