working/business lunch

:  the manner of functioning or operating :  operation

:  engaged in work especially for wages or a salary

:  adequate to permit work to be done

:  assumed or adopted to permit or facilitate further work or activity

:  purposeful activity :  busyness

:  role, function

:  an immediate task or objective :  mission

:  a usually light meal

:  one taken in the middle of the day

:  the food prepared for a lunch

:  to eat lunch

:  to treat to lunch