If you were an uninspired student in high school (like I might have been), then you were probably OK with going home and showing your folks a report card that had a few Cs on it. After all, Merriam-Webster says those Cs showed that your schoolwork was of the “fair or mediocre” caliber.

So where did the letter come from, anyway, and what are some of its uses? Like the letter G, C emerged from the Phoenician letter “gimel.” Centuries later, gimel, which was probably derived from an early sign for “camel,” became the third letter of the Hebrew alphabet.

C is pronounced like an S when followed by any of the front vowels, e, i, and y (e.g., in “receive,” “cider,” “cycle”), but in most other cases, unless it’s followed by an H, is pronounced like a K (e.g., “call,” “come,” “clear,” “crumb,” “epic”).

In the Bible, C can stand for “Christ” (in Christianity considered the divine savior and Lord); “cross” (the place where sins were cleansed); or “church” (the only body connected to Christ).

Based on its numerological significance, the letter C, with its numerical value of 3, is associated with creativity, communication, self-expression and social interaction.

The letter may refer to century, sometimes abbreviated as c. or C., a period of 100 years. On the other hand, if you’re not sure how old something is you can use the trusty letter to stand for “circa,” which comes from the Latin word “circum” and means “around” or “approximately.”

It can also be used to represent one cent (currency), which is also abbreviated c. or ¢, and is a monetary unit that equals 1⁄100 of the basic unit of many currencies. And since C is the Roman numeral for 100, it’s easy to see why the $100 bill is commonly referred to as a C-note.

In the area of science, C stands for carbon, which has an atomic number of 6 on the periodic table of the elements because that’s how many protons there are in its nucleus. In Albert Einstein’s famous equation, E=mc2  the lowercase C stands for the speed of light. (The whole equation stands for “energy equals mass times the speed of light squared.”)

In 1747 Scottish surgeon James Lind discovered that the affliction scurvy, the result of a severe vitamin C deficiency that caused the death of thousands of British seamen, could be treated by consuming oranges and lemons, which are rich in vitamin C.

C can also stand for a few other things, such as “college,” as in “BC” for Boston College. It can mean things as diverse as “cup” in cooking or it can stand for “cargo” when referring to a military transport plane such as a C-130.

In the world of weather, C used to stand for the centigrade temperature scale. In 1948, the name of the scale was changed to Celsius to honor Swedish astronomer Anders Celsius, who’d invented it in 1742.

I’m making a personal effort to replace the Fahrenheit scale with the Celsius one, on which 0 is the freezing point of water and 100 is its boiling point. The idea is an attempt to feel cooler during those ridiculously hot days we had a while back. Let’s face it, saying it’s 35 degrees outside sounds a lot cooler than saying it’s 95. Sitting here in the shade with a Hi-C juice box or some 4C iced tea, I feel cooler already.

Jim Witherell of Lewiston is a writer and lover of words whose work includes “L.L. Bean: The Man and His Company” and “Ed Muskie: Made in Maine.” He can be reached at jlwitherell19@gmail.com.