The phrase "dish in the lab" means preparing or handling small plates or containers with substances or samples in a scientific laboratory setting. Full definition
The researchers then extracted stem cells from the embryos and grew the cells in dishes in the lab. (scientificamerican.com)
So the team grew a few dozen strains of oyster mushroom, testing each for oil - digesting ability in petri dishes in the lab. (discovermagazine.com)
But when dermal papilla cells from humans are put into dishes in the lab, they lose their ability to induce the formation of new follicles. (sciencemag.org)