They called it a “flashlight” because early handheld lights weren’t designed to shine steadily

A student’s short story featuring a treasure hunt at an ancestral mansion uses a vintage name for the mistress of the house a vintage name and supplies a butler, suggesting a Victorian Engliand setting. But the story also used the term “flashlight” — an Americanism for what the Brits are more likely to call an “electric torch”. So I looked up the history of flashlights.The term “flashlight” describes how the early battery-powered portable lights worked… in bursts, or flashes, rather than a steady stream.

From the wonderfully nerdy Flashlight Museum:

Portable electric lights are a relatively recent invention, but actually older than most people think. Searching in a dark closet before 1896, one had to use a candle or kerosene lantern. Accidents occurred and fires followed. A safer alternative was needed. The first trustworthy lighting device was the flashlight, invented about 1896. Portable electric lights were called “flash lights” since they would not give a long steady stream of light. The carbon filament bulbs were inefficient and the batteries were weak, allowing the user to flash the light on for only a few seconds, then release the contact. Very early lights did not have an on/off switch, just a ring or tab that would push against a button or band of metal. When batteries and bulbs became more efficient, the switch was improved. As flashlight became popular, flashlight makers began to add decorative elements to the lights. —Flashlight Museum