impulse
UK[ˈɪmpʌls]US[ˈɪmpʌls]
n
A sudden strong and unreflective urge or desire to act.
n
A driving or motivating force; an impetus.
n
Physics. A force acting briefly on a body and producing a finite change of momentum.
n
Physiology. A signal transmitted along a nerve fiber.
Morpheme Breakdown
im
pulse
im
in
pulse
drive
Etymology
The word 'impulse' entered English in the early 17th century from Latin 'impulsus', meaning 'a push against, pressure, incitement'. This Latin noun is derived from the past participle of 'impellere', meaning 'to drive forward, urge on', which itself is a compound of the prefix 'in-' (here meaning 'into, toward') and the verb 'pellere' (to drive, strike). The core Proto-Indo-European root pel- (to thrust, strike, drive) is the ultimate source, giving the word its fundamental sense of a driving force. Over time, the meaning evolved from a literal physical push to encompass internal psychological urges and brief, powerful signals in technical contexts like physics and physiology, all retaining the core concept of a sudden, motivating drive.
Analysis
Structure: im (in) + pulse (drive)
im: Latin origin, a variant of 'in-', meaning 'in, into, toward'. It functions as an intensive prefix.
pulse: Latin origin, from the root 'puls-', meaning 'to drive, push'. It functions as the core root conveying the sense of a driving force.
Examples
She had a sudden impulse to buy the expensive dress.
The new policy provided a major impulse for economic growth.
A nerve impulse travels rapidly along the axon.