The word dish has several meanings:

1. A shallow container used for serving or eating food. You might eat cereal from a bowl, but serve mashed potatoes in a larger dish. After dinner, someone has to wash the dirty dishes. When people talk about doing the dishes, they mean washing all the plates, bowls, cups, and utensils used during a meal.
2. A particular food or recipe. Spaghetti and meatballs is a classic Italian dish. Your grandmother might have a signature dish she's famous for making. When a restaurant lists its daily special, they're offering a particular dish that changes each day. In this sense, a dish is the complete prepared food, not just the container it comes in.
3. To serve or scoop food onto plates. A cafeteria worker might dish out lunch to students in line. At Thanksgiving, family members might dish up helpings of turkey and stuffing.

The phrase dish it out means to criticize others harshly, while take it means accepting criticism yourself. If someone can dish it out but can't take it, they enjoy teasing others but get upset when teased back.