What does the word "regular" mean if there is a phrase "at the appointed hour"?
The word "lesson" used to mean "spoil", "spoil someone." Hence the word "mutilate", i.e. jinx a person, harm him. A lesson (before schools appeared) meant some kind of action that had to be done, work. For example, a mother gave her daughters lessons: to tighten the yarn, weave canvas, etc. At school, classes also began to be called lessons, i.e. occupations are something that changes, "spoils" the child, he changes from one state (stupid) to another state (smart), he becomes another.
The "lesson hour" at first meant "inevitable," one that would change life. "Oh no, their secret is not mine. I will invariably keep, Until the earth at the appointed hour, Like two friends, will not accept us. // Lermontov. Boyarin Orsha."
Later it began to mean: at the appointed hour (At the appointed hour, we all gathered in the director's office).
Word timed in combination at the appointed hour derived from the noun "lesson", which is an ancient common Slavic word. Modern people associate this word with school time of 45 minutes and with the subject being studied at this time (Russian lesson, math lesson). And in ancient times, they meant any work that needed to be completed on time:
ask the carpenter a lesson.
In principle, a school lesson is a joint work of a student and a teacher. As you can see, the meaning of the word has been rethought and somewhat narrowed.
It comes from the Old Russian verb "recti", that is, "to speak", "to say". From the prefixed verb "urekti" with alternating vowels e // o, the word "lesson" appeared. The expression "at the appointed hour" means "on time", "at a certain appointed time", "on time".
by time, on time, minute by minute, on time, without delay, on time, on time, on time, hour by hour, at the right time. Synonym - without delay.
Here you just need to remember the original meaning of the word "lesson" - this is "memorization", thus, "lesson" is memorable, standing out from the rest. Hence the word "tract" - literally meaning "conspicuous place", which stands out against the background of the rest of the landscape, for example, a wooded ravine in the steppe.