What does it mean to dream yama the god of death?

There is no single, universal meaning to any dream of Yama that applies to all individuals. The meaning of your specific dream depends partly on whether you yourself are Hindu and whether the Hindu Gods play a central role in your personal and family traditions. Very generally, dreams about Death in any form tend to refer to significant life changes, with the end (death) of one phase of life and the beginning of something new. The change might be anything from the end of a school year to the end of a marriage or a career. In any case, the dream does not predict a literal death or a specific future event.