double-action
UK[ˈdʌb.əl ˈæk.ʃən]US[ˈdʌb.əl ˈæk.ʃən]
adj
(of a firearm) able to be fired by either a single pull of the trigger that both cocks and releases the hammer, or by manually cocking the hammer first.
adj
(of a pump, cylinder, or other mechanism) operating or having an effect in two directions or on both forward and backward strokes.
Morpheme Breakdown
double
action
double
twofold
action
operation
Etymology
The term 'double-action' is a modern English compound formed from two distinct Latinate roots. 'Double' originates from the Latin duplus, itself from duo (two) and -plus (fold), conveying the core concept of duality. 'Action' derives from the Latin agere (to do, drive), via actio, signifying a process of movement or operation. When combined, the literal meaning 'twofold operation' logically evolved in mechanical contexts to describe mechanisms, particularly in firearms and pumps, that perform their primary function in two distinct ways or in two opposing directions within a single cycle.
Analysis
Structure: double (twofold) + action (operation)
- double: From Latin duplus (twofold, double). In this compound, it functions as an adjective meaning 'having two parts, twice as much'.
- action: From Latin actio (a doing, performance). In this compound, it functions as a noun meaning 'the process or manner of operating'.
Examples
The detective preferred a double-action revolver for its quicker follow-up shots.
This double-action pump can move fluid on both the upstroke and the downstroke.
The new design features a double-action cylinder that increases efficiency.