There are some amusing derivations of words and expressions.

Consider for example the expression “the dog days of summer”.

The dog days or dog days of summer are the hot, sultry days of summer. They were historically the period following the heliacal rising of the star system Sirius (known colloquially as the “Dog Star”), which Hellenistic astrology connected with heat, drought, sudden thunderstorms, lethargy, fever, mad dogs, and bad luck. They are now taken to be the hottest, most uncomfortable part of summer in the Northern Hemisphere.

The English name is a calque of the Latin dies caniculares (lit. “the puppy days”), itself a calque of the ancient Greek κυνάδες ἡμέραι kynádes hēmérai. The Greeks knew the star α Canis Majoris by several names, including Sirius “Scorcher” (Σείριος, Seírios), Sothis (Σῶθις, Sôthis, a transcription of Egyptian Spdt), and the Dog Star (Κῠ́ων, Kúōn).

From this evolves a discussion of the term calque.

In linguistics, a calque (/kælk/) or loan translation is a word or phrase borrowed from another language by literal word-for-word or root-for-root translation. When used as a verb, “to calque” means to borrow a word or phrase from another language while translating its components, so as to create a new lexeme in the target language. For instance, the English word “skyscraper” was calqued in dozens of other languages. Another notable example is the Latin weekday names, which came to be associated by ancient Germanic speakers with their own gods following a practice known as interpretatio germanica: the Latin “Day of Mercury”, Mercurii dies (later “mercredi” in modern French for Tuesday), was borrowed into Late Proto-Germanic as the “Day of Wōđanaz” (*Wodanesdag), which became Wōdnesdæg in Old English, then “Wednesday” in Modern English.

The names of the days of the week were modeled after the Latin names. The Latin days of the week were named after planets, which were named after gods. The Latin for Tuesday was diēs Mārtis, “Mars’s day,” with Mars being the Roman god of war. And so the Anglo-Saxons swapped out Mars for their Germanic counterparts—in Old English that was Tiu, yielding Tuesday.

The one I like especially is the term indenture. When labourers worked for landowners it was not uncommon to commit the terms of service to writing.  For this purpose the parties would normally attend upon a lawyer particularly because often neither party could read or write. It was at the very least common for the young labourer to be illiterate.  To protect the interests of the parties, the lawyer (after the parties had affixed their mark – usually an “X” – to both copies of the agreement) would fold the duplicate agreement in half or quarters, then cut or indent the top margin of the documents.  When unfolded each copy of the agreement had the appearance of an indented edge. This afforded the parties of a tangible means of proving the identity of the original agreement in the event of a subsequent dispute in a court of law or otherwise.

Sceat

Another term of interest is “scot-free” and lottery.

Scot and lot is a phrase common in the records of English, Welsh and Irish medieval boroughs, referring to local rights and obligations.

The term scot comes from the Old English word sceat, an ordinary coin in Anglo-Saxon times, equivalent to the later penny. In Anglo-Saxon times, a payment was levied locally to cover the cost of establishing drainage, and embankments, of low-lying land, and observing them to ensure they remain secure. This payment was typically a sceat, so the levy itself gradually came to be called sceat. In burghs, sceat was levied to cover maintenance of the town walls and defences.

In Norman times, under the influence of the word escot, in Old French, the vowel changed, and the term became scot. In 19th century Kent and Sussex, low-lying farmland was still being called scot-land. Scot, though, gradually became a general term for local levies; a person who was not liable for the levy, but received its benefits, got off ‘scot-free’.

Lot means portion/share, hence lottery, land lot and allotment. The phrase scot and lot thus meant the local levies someone paid, and the share they received of local provisions; more generally, it meant rights and obligations, in respect of local government.