# Barlow lens

> English word · Noun

## Definitions
1. A diverging lens which, used in series with other optics in an optical system, increases the effective focal length of an optical system as perceived by all components that are after it in the system.

## Etymology
Named after British mathematician and physicist Peter Barlow (1776–1862).

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/barlow-lens