Here's a breakdown of its evolution:
1. Regula: This Latin word originally meant "rule, standard, regulation, or straight line". It was used in the sense of a guiding principle or a straight edge used for measuring or drawing.
2. Regulus: This is the Latin word for a small king or a little ruler.
3. Ruler: Over time, the term "ruler" evolved to encompass both the meaning of a "straight edge" and a "person who rules". This dual meaning developed due to the association of rulers with governance, as they often used straight edges for legal documents and maps.
Interestingly, the word "ruler" for a straight edge is considered a doublet, meaning it's a word that evolved from the same root word as another word, but with a different meaning (in this case, "rule" as in "to govern").
So, the next time you use a ruler to draw a straight line, remember its long history and the connection it has to the concept of governance!