periscope

noun2

1. •
   A form of viewing device that allows the viewer to see things at a different height level and usually with minimal visibility.
2. •
   (no longer used) A general or comprehensive view.

   • […] will show it not only enlarging the periscope of knowledge, but contributing to the amelioration of the condition of unfortunate and suffering humanity […] — 1885

verb1

1. •
   To rise and peer around, in the manner of a periscope.

   • Thousands of ungainly black-beaked heads would periscope and freeze in the direction of the approaching intruder. — 1951

verb1

1. •
   (Internet) To broadcast live video stream using Periscope app via phone or tablet.

   • Presidential candidate Hillary Clinton Periscoped her first major campaign rally with Olympian Michelle Kwan as the host of the live stream. — 2015