light water

American  

noun

1. ordinary water, as opposed to heavy water; water containing the normal proportion of deuterium oxide.

---

light water British  

noun

1. a name for water (H 2 O), as distinct from heavy water

---

light water Scientific  

1. Ordinary water, H ₂ O.

2. Compare heavy water

---

Etymology

Origin of light water

First recorded in 1930–35

Example Sentences

"Moreover, in landscapes affected by today's and tomorrow's disturbances, naturalized species can make it even harder for native trees to survive, because competition for light, water, and nutrients intensifies," he adds.

From Science Daily • Feb. 9, 2026

The new pools are intended to handle year-round use, incorporating electric pool heaters, salt water and UV light water treatment.

From Los Angeles Times • Jul. 2, 2025

But millions have been left without light, water or heat as winter sets in.

From BBC • Nov. 25, 2022

Lyash told the board Thursday that for the Clinch River site, the TVA is focused on GE Hitachi’s design for a small modular reactor that uses light water like all U.S. commercial reactors.

From Seattle Times • Feb. 10, 2022

As if it were not perfectly notorious that in the articles of light, water, and air, Nature outran the constable.

From Harper's New Monthly Magazine, No. V, October, 1850, Volume I. by