Terrorism is the use or threat of violence against random or symbolic targets in pursuit of political aims.
Definition Two:
Terrorism is the use of violence or the threat of violence to achieve political, social, or economic ends. Although many restrict the term to only those acts committed by non-governmental groups, state terrorism is also a major factor in the social world.\
Definition 3.
Terrorism is the unlawful use of violence or threat of violence, often motivated by religious, political, or other ideological beliefs, to instill fear and coerce governments or societies in pursuit of goals that are usually political.