Fifty years ago, Neil Armstrong and Buzz Aldrin became the first people to walk on the moon. Unfortunately, all they brought back were some rocks.\n\nBut the moon has given us many things, including several words! So let\u2019s celebrate this landmark in space exploration by looking at the etymology of \u201cmoon,\u201d plus five words it has inspired.\nMoon Etymology\nThe word \u201cmoon\u201d has a long history, which is unsurprising given that it\u2019s a massive glowing orb in the night\u2019s sky that has been around for longer than human language. We can, however, trace it back to both the Middle English mone and the Old English mona.\n\nFurther back, it may come from the Proto-Indo-European term *me(n)ses- and the root *me-, meaning \u201cmeasure.\u201d Here, we see how people have used the waxing and waning of the moon to measure the passage of time since\u2026 well, since we\u2019ve had any notion of time passing.\n\n[caption id="attachment_13987" align="aligncenter" width="450"] Waxing and waning...(Image: Orion 8\/wikimedia)[\/caption]\n\nAnother term we may want to look at is \u201clunar,\u201d an adjective meaning \u201crelated to the moon.\u201d This comes from the noun luna, an old-fashioned word with origins in the PIE root *leuk-, meaning \u201clight\u201d or \u201cbrightness.\u201d And here we see the importance of the moon as a source of light at night.\n\nBut how have these terms influenced modern English? Let\u2019s take a look.\n5 Words that Come from the Moon\nThere are many, many words with a connection to our lunar neighbor. And we won\u2019t even touch on figures of speech such as over the moon and once in a blue moon. But we will look at five of our favorite moon-derived terms to see where exactly they come from.\n1. Moon as a Verb\nAs well as a noun, \u201cmoon\u201d has picked up two key uses as a verb over the years:\n\n \tTo act absent-mindedly, often through distraction (e.g., to \u201cmoon over\u201d someone or to \u201cmoon around\u201d the house when you have nothing to do).\n \tTo expose one\u2019s buttocks as a joke or insult.\n\nThe first of these is probably related to the word \u201cmoonstruck,\u201d which reflected an old belief that the moon could affect people\u2019s behavior (more on that below). The second comes from the fact that buttocks can be pale and round, much like a certain feature of the night\u2019s sky. We hope learning this doesn\u2019t prompt you to see the moon as a big sky buttock, though.\n2. Month\nOriginally, a \u201cmonth\u201d was literally the time between one new moon and the next one. As such, we can find connections between \u201cmoon\u201d and \u201cmonth\u201d in many European languages. In fact, the PIE term *me(n)ses- above may have originally meant both \u201cmoon\u201d and \u201cmonth.\u201d\n\nAnother word we get from \u201cmoon\u201d is \u201cMonday,\u201d which literally means \u201cday of the moon.\u201d We also see this in the German Montag, as well as the French lundi, the Spanish word lunes, and the Italian term lunedi.\n3. Menstruation\nMoving on from \u201cmonth,\u201d we have a monthly cycle: menstruation. In fact, \u201cmenstruation\u201d and \u201cmenses\u201d come from Latin and Greek words meaning \u201cmonth\u201d (mensis) and \u201cmoon\u201d (mene).\n\nSome people also believe their menstrual cycles sync up with the lunar cycle. However, there is no scientific evidence for this, so it is probably a myth.\n4. Lunatic\nAbove, we mentioned the old belief that the moon can affect people\u2019s behavior. We see this most clearly in the word \u201clunatic,\u201d which now refers to someone who behaves erratically.\n\nNot that long ago, though, \u201clunatic\u201d was a word for someone suffering from mental illness. And some people still believe the moon can affect our behavior. But medical science has moved on from such ideas, so we do not use this word to refer to mental illness any more.\n5. Moonshine\nWhat better way to finish our list than with a drink? Having said that, we\u2019re not sure how many of you would pick moonshine as your beverage of choice.\n\nIf you buy moonshine today, it will probably be from a shop. But the term was first applied to smuggled or illegally distilled liquor, illicit activities that always occurred at night. It may also be related to the word \u201cmoonraker,\u201d which is associated with English smugglers for the same reason.\nThank You, Moon\nFinally, let us say a brief thank you to the moon. Sure, with modern science we know it\u2019s a big hunk of rock that just sits in the sky, not some god or goddess watching over us. But it has been with us since before humanity had the gall to shape tools from flint, never mind strap ourselves to rockets and blast off into the void to pay it a visit. And we see that influence across human culture, art and \u2013 as shown above \u2013 language.\n\n[caption id="attachment_13985" align="aligncenter" width="451"] We salute you, moon![\/caption]\n\nAs a species, then, we owe the moon a lot. And that\u2019s before we even get on to its role in controlling the tides. So next time you use the word \u201cmonth\u201d or \u201cmenstruation,\u201d spare a thought for our lunar friend.