noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   An apparatus for viewing the Sun without harming the eye, by means of an optical filter that attenuates most of the sunlight while allowing only a small amount of the solar radiation.

Etymology

From helio- + -scope.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.