I suspect TERROR is a condition of MODERNITY, best summarised by the SILENT SCREAM articulated by Munch.
Image Source: https://www.munchmuseet.no/en/The-Scream/where-can-i-see-the-scream/
This form of TERROR is abject FEAR, DREAD, ANXIETY & UNCERTAINTY.
In last 25 years, it has been dominated by DISCOURSES evolving around Sept 11. But I would say that the THEATRICS OF SEPTEMBER 11 is much more about TRAUMA, NOT TERROR.
In the so-called Western World, the current TERROR that can not be named is the RISE OF THE FAR RIGHT. Most of us who are by-standers, it's mainly DREAD that inhabits in our COLLECTIVE TERROR.
Those of us who reside in Democratic Jurisdictions, it's a question of CIVIC DUTY...