This is a list of words or popular sayings that we all use from time to time. Most of them have strange origins, which at first glance seem hard to believe. In addition, many also have "mythological" beginnings, which are mistakenly believed.
See also: 10 Wrong Words That Are Actually Correct
10 Upper Crust
Meaning: Elite or Aristocracy  Myth: During the Middle Ages, life was difficult, especially for the people living in poverty. For the rich or noble, however, life was much easier and they had a range of luxury goods that most others did not possess. One of these luxury items was the selected piece of bread, which in this case was the top of the bread. However, there is no evidence that it has ever been used in this way. While there is a 15th-century example stating that you "should tailor the upper crust to your sovereign …", it does not necessarily mean that only the nobility could eat it.
Reality: The first documentary mention of "upper crust" in relation to the elite was in 1823 and in those days it was used to refer to a person's head or hat. (Alternatively, it was also used to describe the "Upper crust" thus actually refers to the people at the head of society. 
9 Toe the Line
Meaning: Behavior or action according to the rules
Myth: Diffuses due to the spelling mistake "Tow the Line", which results from a linguistic term called "ovule", in which a word or phrase is misunderstood and then misinterpreted, many people believe that it is a boat or another vehicle, This makes a lot of sense when you realize that ropes and cables on ships are sometimes called "leashes." Some people also falsely believe that it is has to do with an old practice in the British Parliament that prevents MEPs from killing each other.
Reality: First, it is called "toe the line," and the first mention was in 1813. The end of the phrase contains a series of words, including marks, scratches, or tears. ("Up to scratch" is another one from the same place.) However, they all referred to the practice of putting one's feet on a certain line before a race or other company. Someone who shows the line does what is expected of him. In politics, use often occurs, especially among people who are heavily divided among partisan groups, as their members are often said to follow the party line. 
8 Brand Spanking New  Meaning: Completely New
Myth: People believe that it corresponds to a newborn baby who needs to be beaten to ensure that it can cry. However, spanking in the sense used in this sentence is just a clarification to emphasize how new something is, and it eventually entered the English lexicon in the 17th century. Moreover, the way beating is used in this sentence has nothing to do with hitting someone. it simply means "exceptionally big or fine".
Reality: The first recorded use of the phrase was in 1860 and may have come from the phrase "brand span new", which was used much earlier. The word span may have been converted to spanking to increase the intensity of the phrase. Brand new is also the reference to the hot iron, with which the cattle breeders marked their livestock. This term was first used in the 16th century. 
7 Respiratory arrest
Meaning: Muted breathing, usually due to emotions 19659005] Myth: Another often misspelled phrase that is often changed to "bait breath", which makes people believe that it has something to do with it the filing of a trap or waiting. Which is ridiculous, because how could you take someone's breath away?
Reality: For the true origins, we must return to The Bard, William Shakespeare. The phrase first appeared in his play The Merchant of Venice, written in 1598. (The play is more famous for the character Shylock and his speech, in which he asks, among other things, "Does not a Jew have hands … If you sting us, do not we bleed?") He took the word "diminished or diminished in power" and shortened it is limited to. However, we no longer use the word "Bated" or the verb "Bate", so the phrase may change to "Baited Breath" forever. 
6 Crow flying
Meaning: In a straight line to circumvent all obstacles
Myth: Medieval British barges are said to have a cradle cage with which they land found. Crows were said to hate water and would fly directly ashore, and because they were flying, the crows could see the land much farther than the sailors on the ship. They should also be kept at the top of the mast, which is why the vantage point in the view of the proponents as Krähennest was called.
Reality: The first use was recorded only in the 18th century, and almost all examples refer to landings distances. (In fact, the first documented use of the term seems to be a slightly racist opinion of the Spanish people.) On-ground observers noticed the crows flying around doing this in a straight line, and the trees, rivers, or buildings missing what people did disabled people. 
5 A Kangaroo Court
Meaning: An Illegal, Forged Court
Myth: Since kangaroos are native to Australia, it is widely believed that they are of Australian origin and relate to it. An Aspect of Nature the kangaroos, the malignancy a kangaroo shows, or the way your jumping seems to defy the laws of nature. Kangaroo courts may be notoriously vengeful and seem to "jump" over evidence that could relieve the accused.
Reality: The phrase, first used in America in 1849, described a process that was a delusion. Before the sentence went extinct, they were sometimes called "mustang dishes." This knowledge helps to explain the true meaning: the dishes were named because the animals are wild and unpredictable. Kangaroos were probably used for their comic nature, at least from the point of view of the Americans. 
4 Do not throw the baby out with the bathwater
Meaning: Do not throw anything valuable away with the trash
Myth: In the Middle Ages, babies should have been last washed in the bath because they were considered the least important of the family. Because of the immense amount of dirt accumulated by the rest of the family during work, the water was so dark that the baby could not be seen and the mother threw the baby out along with the used bath water. The notorious Karl Pilkington once passed this story on and even claimed that the baby was washing himself.
Reality: The sentence comes from an old German proverb without any real basis. The writer and satirist Thomas Murner was the first to write this down, in 1512 in his book An Appeal to Fools. It should only illustrate the need to take care of your valuables. 
3 It's all Greek to me
Meaning: Something is incomprehensible
Myth: This sentence is generally attributed to William Shakespeare, because he used it in his play Julius Caesar in 1601. In His play used the sentence of Casca to explain to Cassius that he could not understand anything that was said to him. ("… those who understood him smiled and shook their heads, but for me it was Greek.")
Reality: Shakespeare was not only beaten to death by another playwright (Thomas Dekker) ), the origin of the phrase is much earlier than either; it comes from a medieval Latin proverb that meant, "It's Greek; it can not be read ". The reason the authors used this sentence was that the knowledge of reading Greek was lost to most of the world. It is one of the few phrases that has retained its original meaning since its introduction over the centuries. 
2 It's not over until the fat lady sings
That is, nothing is over until it's over.
Myth: A fat singer named Kate Smith has sung God Bless America for the NHL's Philadelphia Flyers. The team recorded it and, as a lucky charm, often asked to play it live as it became their unofficial anthem. The sheer number of victories played when the song was played (fifty-two victories over seven defeats in the first eleven years) meant that no game was out of reach until Smith sang.
Reality: The first recorded mention has nothing to do with sport; A 1976 booklet entitled Southern Words and Sayings states: "The Church is not out until the fat lady sings." The first mention she made in the national lexicon was one NBA coach, Dick Motta, who was after the score of a game: "The opera is not over yet, until the fat lady sings." (This is closely related to the fact that the sentence is often associated with Brunnhilde
As for the claim that Smith's singing was the inspiration, there is a small but important contradiction: she sang before the game even began. 
1 Kick the Bucket
] Meaning: Die
Myth: When someone got ready to hang, he stood on a bucket and tied the noose around the neck. After working the nerve to cope with it, they pushed the bucket away with their foot so they would die.
Reality: The "bucket" part of the phrase corresponds to the French word "buque", which means "yoke" or "piece of wood". (This is a disposable bucket used in 16th-century England.) When a pig was hanged on a beam to be slaughtered, it banged around. As they hung on their feet, the pig eventually stepped against the beam or the buque. Shakespeare used this meaning of the word bucket in his play Henry IV: "Faster than the one who reaches for the Brewers Bucket". ("Gibbet" used to mean "hang".)