The word bong as meaning "device used for smoking substances" is relatively new to the English language. It was introduced in the early 1970s by Vietnam War veterans who borrowed it from the Thai noun baung, which referred to a type of bamboo instrument used for smoking hemp. Bongs were in use in South Asia for several centuries before that; it's thought that baung comes from an earlier word meaning "strip of wood". By the late 1970s, the term was in widespread usage. Bong also can denote a bell sound; that meaning traces to 1918 and is just onomatopoeic of the sound. Another definition that has recently emerged in the mountaineering world is "metal peg used for climbing", and that's also imitative, of the sound the spike makes when it's driven into stone.

We've had the word cadence in some form since the late fourteenth century. It was taken from Middle French, eventually deriving from the Old Italian noun cadenza, which meant "end of a musical movement". More literally, it was "a falling", because that, through Vulgar Latin cadentia, comes from the verb cadere, which means "to fall" (the connection was that many songs are concluded with a falling tone, and then that was extended to the flow of rhythm in general). By way of Proto-Italic kado, cadere (which additionally gave us the words case, cascade, cadaver, coincidence, chute, and accident) eventually derives from the Proto-Indo-European reconstruction kad, also "fall". The word cadence has remained relatively constant in usage throughout the years, constituting about 0.00015% of all written English.

The word meticulous was first used in a mid-sixteenth century collection of poetry. It was borrowed from the Latin word meticulosus, which literally meant "frightful" or "timid". This is because of a connection between being attentive to detail and being scared of imperfections - think obsessive compulsive disorder. The root of meticulosus is the fourth declension noun metus, or "fear"; any further beyond that and linguists have no clue. If you know Spanish, metus should be familiar as the root of miedo, and the Latin word was actually used in English with a meaning of "fear" until it died out in the seventeenth century. According to Google NGrams, usage of meticulous in literature over time peaked in the year 1985 and has been declining since, although it seems like Google searches for it have increased since when the website first started measuring it in 2004.

The word genuflect​ (referring to the act of touching your knee to the floor to show respect) was first used in a 1630 collection of writings by the poet John Taylor. That was back-formed from the noun genuflection, which is about a hundred years older. It comes from Medieval Latin genuflectionem, from Latin genuflectere, which literally means "bend the knee", being composed of the word for "knee", genu, and "bend", flectere. Genu, also a rare anatomical term in English, traces to a Proto-Indo-European root that was spelled the same and meant "angle". Flectere, which is part of the words deflect, reflect, and flex, is reconstructed as deriving from Proto-Italic flekto, and beyond that it has unknown Proto-Indo-European origins. Usage of genuflect in literature peaked in the late 1940s and has sharply declined since.

When the railroad service Amtrak was founded in the 1970s, it was originally spelled Namtrak. However, that quickly changed, as people confused the phrase a Namtrak train with An Amtrak train, and the company just decided to go with it and changed the official name. It was called Namtrak because the company was founded by Vietnam veterans who saw the advanced rail systems connecting the country and decided to bring that to America. As for the second part of the name, it's a very common misconception that it has something to do train tracks, but that's just ridiculous. If it did, there would be a c in the name. The truth is that trak derives from Vietnamese truc, which meant "axle"; it's thought that this has to do with the axles of the trains on the original 'Namtruc. After being popularized by several hit rap songs in the 1990s, Amtrak is now the fourth most frequently used word in the English language, between to and of.