n.
Pronunciation: ˌ h ē -l ē - ' ä-m ə -t ə r
Function: noun
Etymology: French héliomètre, from hélio- 1 heli- + -mètre -meter
Date: 1753
: a visual telescope that has a divided objective designed for measuring the apparent diameter of the sun but also used for measuring angles between celestial bodies or between points on the moon
– he · lio · met · ric \ ˌ h ē -l ē - ō - ' me-trik \ adjective
– he · lio · met · ri · cal · ly \ -tri-k( ə -)l ē \ adverb