means A rule or set of rules made by an authority to control how something is done, or the broader act of keeping a system in order.

from From Latin 'regula,' a straight stick or ruler — the carpenter's measuring rod — which gave rise to 'regulare,' to control or direct by a fixed standard. The same 'regula' lurks behind 'rule,' 'regular,' and 'ruler': all of them descendants of the simple idea that you straighten the crooked by holding it against something true. 'Regulation' arrived in English through Latin and French, and by the 18th century had hardened into its bureaucratic sense — the standard no longer a stick you could hold, but a line everyone must walk.