Etymon #1
Watching to wagering
Borrowed from scholarly Latin, the verb entered English in 1599. The Latin root carried a physical image, a watcher in a tower scanning the horizon, but the earliest English meaning was already metaphorical: the mind's careful attention, the act of contemplation.
Three routes carried this word into English. The noun came through Old French in the late 1300s. William Caxton tried to borrow the verb directly from French in the 1480s, but it didn't take. The verb that survived arrived through Latin in the 1590s.
In Latin, the source verb meant to watch, to observe, to keep something in view. It descends from an older Proto-Indo-European root meaning to look. The original sense was bodily and immediate, fixed on whatever the eye could reach.
The same Proto-Indo-European root passed through Greek and produced English words including SCOPE, TELESCOPE, and HOROSCOPE. All are about looking closely, with care.
