In English, many of our words come from three major language groups (Latin/Romance, Greek, and Germanic). In this case, etymology is rooted in the Greek language. It can be broken down into two parts: etymon (Greek word meaning "literal meaning of a word according to its origin") and the suffix -ology (Greek for "the study of {subject}"). Etymon can further be broken down into etymos, meaning "True". The word etymology has been used in the English language as far back as the 14th century (1300s CE). (Merriam-Webster, n.d.)

Okay, but what about something a bit more interesting or whacky? What about popular English idioms? This is where things get really interesting, especially when you consider that multiple cultures may exist within a spoken language. For example, the vocabulary and idioms used on the daily differ from a British person to an American person to an Australian person, etc. Since I am American, I will be sharing some examples from American English. Here are the brief origins of some of my favorite idioms used in American English (though not necessarily originating from it). 

1. "mad as a hatter": This phrase is used to refer to someone who exhibits eccentric, crazy, or strange behaviors. It derives from the 18th-20th century practice where hatters (professional craftsmen who make hats) would use the element known as mercury during the hat-making process. Mercury is highly toxic, and being exposed to it for a long time can cause many physical and mental health issues. It would often happen that hatters would "go insane" or exhibit these eccentric behaviors later in their years. (White, 2022)
2. "The time is ripe.": This phrase comes from a famous American Civil Rights activist by the name of Martin Luther King Jr. It refers to the current time or situation being perfect for a given action. For example, "The time is ripe to put the house up for sale." MLK Jr. advocated for equal rights for African Americans, who have historically been mistreated in American society. Specifically, this phrase derives from a quote by King where he says "The time is always ripe to do the right thing." 'Ripe' in this context has agricultural roots. In English, ripe refers to the period when a fruit is perfectly ready to be eaten or cooked. The window of time where a fruit is ripe is typically short, after which it begins to go bad (or rot). In his quote, King is saying there is never a singular 'best' time to do what is right, because it is always the best time to do what is right. (White, 2022)
3. "break the ice/icebreaker": This phrase means to relieve tension, or to prepare the way for an event or activity. Originally, 'breaking the ice' was much more literal, and referred to the breaking of ice on the ocean surface when ships were moving through cold areas (in particular in Northern waters). An 'icebreaker' was, and still is, a type of ship specifically designed for optimal (best) movement through ice-covered waters and equipped to break up that ice for other ships that may need passage. In today's English-speaking world, the term 'icebreaker' is often used during meetings or classrooms where many of the participants are unfamiliar with one another. An icebreaker in this context might be simply a discussion about everybody's interests or backgrounds, or an activity designed to help people get to know one another. You will likely have encountered this in your language learning journey if you have attended a classroom setting. It is a popular way to relieve any shyness or awkward tension between students who do not know each other. (White, 2022)

Resources: 
Merriam-Webster. (n.d.). Etymology. Merriam-Webster. https://www.merriam-webster.com/dictionary/etymology
White, K. (2022, February 25). Exploring the Origins of Idioms. The Henry Ford. https://www.thehenryford.org/collections/explore/articles/exploring-the-origins-of-idioms