The word 'triggered' originates from the earlier noun 'trigger,' which entered English in the 17th century from the Dutch 'trekker,' meaning 'pull' or 'that which pulls,' specifically the lever of a crossbow or firearm. The core concept is a mechanism that, when pulled, initiates a larger, often rapid and powerful, sequence of events. This literal sense of 'setting off a device' evolved metaphorically to mean 'initiating any process.' The modern adjectival usage, describing a strong emotional or psychological reaction, is a direct extension of this metaphor: an external stimulus 'pulls the trigger,' setting off a pre-existing, often intense, internal response linked to past experience.

Structure: trigg (pull) + er (agent/instrument suffix) + ed (adjective/verb suffix) - trigg: From Dutch trekker (that which pulls, a trigger), from trekken (to pull). Its functional role is the core root meaning "to pull." - er: An English agentive suffix, here indicating an instrument or thing that performs an action (e.g., "puller"). - ed: A suffix forming the past tense and past participle of verbs, and subsequently adjectives from those participles (e.g., "a pulled lever" -> "triggered").