kabarnit and cyber

 A phrase often used in eulogies (too frequently heard these days) is taken from this passage Bava Batra 91a-b:

And Rav Ḥanan bar Rava says that Rav says: On that day when our forefather Abraham left the world, the leaders of the nations of the world stood in a line, in the manner of mourners, and said: "Woe to the world that has lost its leader, and woe to the ship that has lost its captain."

ואמר רב חנן בר רבא אמר רב אותו היום שנפטר אברהם אבינו מן העולם עמדו כל גדולי אומות העולם בשורה ואמרו אוי לו לעולם שאבד מנהיגו ואוי לה לספינה שאבד קברינטא

The word translated here as "captain" is קברניט kabarnit. It's a post-biblical word, parallel to the biblical rav chovel  רב חובל - "chief sailor" (as found in Yonah 1:6). Kabarnit is borrowed from the Greek kybernetes (steersman), which derives from the verb kybernan (to steer, guide, govern).

From Greek, this same root entered Latin, where it eventually gave us the word "govern":

late 13c., "to rule with authority," from Old French governer "steer, be at the helm of; govern, rule, command, direct" (11c., Modern French gouverner), from Latin gubernare "to direct, rule, guide, govern" (source also of Spanish gobernar, Italian governare), originally "to steer, to pilot," a nautical borrowing from Greek kybernan "to steer or pilot a ship, direct as a pilot," figuratively "to guide, govern"

A much more recent use of the Greek root was by the Jewish American mathematician, Norbert Wiener. He used it to coin the term "cybernetics":

"theory or study of communication and control," coined 1948 by U.S. mathematician Norbert Wiener (1894-1964), with -ics + Latinized form of Greek kybernetes "steersman" (metaphorically "guide, governor"), from kybernan "to steer or pilot a ship, direct as a pilot"

In the 1990s, when use of the internet began spreading rapidly, the first half of cybernetics was taken as a prefix: "cyber." At the time, it was used it was used to describe anything internet related, and the internet as a whole was known as "cyberspace." 

The broad use has declined since then, and today it is primarily used in the term "cybersecurity". In fact, in Israel, the use of just "cyber" סייבר alone refers to the field of internet and data security.