Some scholars argue that clock is one of the few common words to come into English from Celtic (cloc), while others claim its origin is in Middle Low German klocke, from medieval Latin clocca. Wherever it came from, its original meaning was “bell.” It’s likely that, like owl, it’s an onomatopoeic word; in this case, it may have been inspired by the rattling, clacking noise that early sheet-iron handbells made.
Ostracize comes to us from the Greek word ostrakizein, which came from ostrakon, meaning “shell or potsherd.” Why? Because, around 506–322 BC in Athens, there was a procedure called ostracism, in which any citizen could be expelled from the city-state for ten years. Each year, Athenian citizens had the opportunity to hold an ostracism; if they chose to, citizens would write the name of a person they wanted to expel onto potsherds (ostraka). Officials would tally the ostraka, and if there were enough, they would banish the person with the most votes.