spyglass

[spahy-glas, -glahs] /ˈspaɪˌglæs, -ˌglɑs/
noun
1.
a small telescope.
Origin
1700-10; spy + glass
British Dictionary definitions for spyglass

spyglass

/ˈspaɪˌɡlɑːs/
noun
1.
a small telescope
Word Origin and History for spyglass
n.

also spy-glass, "telescope, field-glass," 1706, from spy (v.) + glass (n.).