Trauma is defined as an event, series of events, or set of circumstances that is experienced by an individual as physically or emotionally harmful or life threatening and that has lasting adverse effects. Traumatic events range from one-time incidences to experiences that are chronic and even generational. 

Acute trauma refers to a one-time event, such as an earthquake, fire, assault, or car accident.
Chronic trauma refers to traumatic experiences that are repeated and prolonged, such as ongoing exposure to family or community violence, chronic bullying, or a long-term medical issue.
Complex trauma refers to exposure to multiple traumatic events from an early age, often within the caregiving system or without adequate adult support, which has short and long-term effects in many areas. Examples include abuse and neglect within families, witnessing domestic violence, or experiencing other forms of violence or adversity without adequate adult support.
Historical trauma refers to the collective and cumulative trauma experienced by a group across generations that are still suffering the effects. This includes discrimination, violence, and oppression of particular groups. Racial or race-based trauma refers to experiences of racially driven discrimination, harassment, and systemic oppression. (https://safesupportivelearning.ed.gov)