PTSD is a mental condition triggered by witnessing a terrifying event. Flashbacks, nightmares and anxiety often accompany it. It can last for months or even years.
Emotional trauma refers to the response we have to a deeply distressing event, and it often overwhelms our ability to cope. This leads to feelings of helplessness.
Therefore, trauma is always part of PTSD, but all trauma doesn't necessarily lead to post-traumatic stress.