The phrase
"lunch downtown" means having a meal in a restaurant or cafe located in the central part of a city during the midday hours.
Full definition
Tomorrow I'll treat myself and my girls (sis + daughter) with
a lunch downtown and small shopping for the props / upcoming photo shoots which will, hopefully be a bunch so that I can get all of this creativity out
We completed the whole zoo in about 2 hours and had enough time to visit Lighthouse Place Premium Outlets for a little shopping and
lunch downtown.