What you might call a raita in the North of India is called a pachadi in the South and a Tambli elsewhere.It is a dish typically made of finely chopped or blended cooked vegetables with yoghurt, coconut, green or red chilies and tempered in oil with mustard seeds, ginger and curry leaves.
Pachadi means pounded. In the states of Kerala and Tamil Nadu in South India, pachadi is eaten fresh and commonly eaten with rice and a lentil curry. There are many varieties made of the same key recipe.
There is no real approximation to a pachadi outside of India. The closest in western cuisine is a side dish or dip, or a yoghurt salad. It is sometimes incorrectly referred to as a condiment, but unlike traditional western condiments like salt, pepper, mustard and horseradish that made dishes more spicy, these dishes have a cooling effect from the yoghurt, to contrast with spicy curries.
It is also sometimes called a pickle – this is incorrect, at least in the states of Tamil Nadu and Kerala. However, dishes of the same name can be totally different in different states of India, so there might be other states where a pachadi is more like a pickle.