dynamo

noun

dy·​na·​mo ˈdī-nə-ˌmō 

plural dynamos

1

: generator sense 1b

2

: a forceful energetic individual

Did you know?

The dynamo was introduced in 1867 to produce electricity for commercial use. Like all later generators, the original dynamos changed mechanical energy (produced by steam, which was itself produced by burning coal) into electricity. The word is less used today than it once was, since it's often applied only to generators that produced direct electric current (DC) rather than alternating current (AC), which is now the standard. A human dynamo is a person who seems to have unlimited energy.

Synonyms of dynamo

• pistol
• powerhouse

Examples of dynamo in a Sentence

a dynamo who barely needs to sleep, or so it seems

Recent Examples on the Web

Gillis was omnipresent at her son’s Detroit events — a small dynamo of a woman who was always around for big moments at his Third Man Records complex and backstage at his shows, going back to his White Stripes days in the ’90s and ’00s. —Brian McCollum, Freep.com, 15 Mar. 2026

Ditto at the rain-free Humphreys debuts of gospel-music legends The Blind Boys of Alabama, Brazilian music superstar Milton Nasciemento, solo guitarist Stanley Jordan, blues vocal dynamo Shemekia Copland, Portuguese fado singing star Mariza and, in 2017, the pioneering art-rock band King Crimson. —George Varga, San Diego Union-Tribune, 8 Mar. 2026

In recent days, OpenAI signed a Mountain View lease that will enable the artificial intelligence dynamo to launch a big expansion into the South Bay. —George Avalos, Mercury News, 2 Mar. 2026

Pinning down when — and how — the moon’s dynamo operated offers clues about how its core cooled, how its mantle evolved, and why its geologic activity faded. —Stefanie Waldek, Space.com, 27 Feb. 2026

Word History

Etymology

short for dynamo-electric machine, translation of German dynamo-elektrische Maschine; dynamo-elektrisch, probably by inversion of elektrodynamisch electrodynamic

Note: According to the Oxford English Dictionary (first edition, 1897), "The full name dynamo-electric machine was given by [Werner] Siemens in 1867, to distinguish his invention from the magneto-electric machines previously used, in which the electric current was generated by means of a permanent magnet." This statement appears to be based on a citation from The Times (December 5, 1882), according to which, "Professor Thompson [not further identified] said that the name 'dynamo-electric machine' was first applied by Dr. Werner Siemens in a communication made in January, 1867, to the Berlin Academy." The communication in question was "Ueber die Umwandlung von Arbeitskraft in elektrischen Strom ohne Anwendung permanenter Magnete," published in Annalen der Physik und Chemie, Band 130 (1867), pp. 332-35. The article does in fact describe a generator with rotating coils, but nowhere does Siemens use the word dynamo-elektrisch or the phrase dynamo-elektrische Maschine; the closest he comes is magnetelektrisch for the opposing term. The first appearance of dynamo-elektrisch must date some time after this.

First Known Use

1882, in the meaning defined at sense 1

Rhymes for dynamo

• afterglow
• akimbo
• albino
• aliquot
• allegro
• amigo
• apropos
• audio
• bungalow
• calico
• calypso
• cameo

Kids Definition

dynamo

noun

dy·​na·​mo ˈdī-nə-ˌmō 

plural dynamos

1

: generator sense a

2

: a forceful energetic person