The expression "keep like the apple of your eye" is used quite often. It means "to treat something very carefully." But a modern person in this idiomatic phrase does not understand all the words, and the most strange sounds "apple".
Where did it come from?
The expression "to keep like the apple of an eye" is very old, it came into modern Russian from Old Church Slavonic. "Zenitsa" can be found in "The Lay of Igor's Campaign", and in the old translation of the Bible, and in the verses of Russian poets who loved archaisms. Over the course of several centuries, the Russian language has changed, new words have appeared in it, and many of the old ones have fallen out of use or have remained only in idiomatic expressions that are not always understandable to a modern Russian.
Some expressions were once used in a particular professional environment and were understandable to everyone, but with the disappearance of the profession they disappeared from everyday speech.
The eye and what is in it
The second part of this expression is more or less clear. The word "eye" has been preserved in almost all Slavic languages - Russian, Ukrainian, Belarusian, Polish, Czech, Slovak and others. It means "eye". In the Russian language this word has become the property of the "high calm", in other Slavic languages it refers to the usual everyday vocabulary.
This word is often heard in songs and romances - just remember "Black Eyes", "Black Eyebrows, Brown Eyes", etc.
What is in the eye?
Examine the eye. You can take a picture, you can look in the mirror. You will see that it consists of several parts. There is an eyeball, there is an iris, and there is a pupil. He is the most important thing in the eye. Now, of course, damage to the pupil is sometimes treated, but in ancient times a person with the slightest injury to the pupil could go blind. It was this black speck in the center of the eye that was called the apple, and it was it that had to be protected.
An eye for an eye a tooth for a tooth
In Ancient Russia, as in any state, there were their own laws. To a modern person, they may seem cruel, but people of that time could not otherwise maintain order. And since those times the expression "an eye for an eye" has gone - again about the eyes. If we translate it into modern language, it will sound something like this: "repay in the same coin", "do to a person what he did to you." The eye is mentioned because in ancient times people especially appreciated sight. The blinded person very quickly found himself at the bottom of the social ladder, unless he was a representative of the ruling clan. Most of the crafts and military service were inaccessible to him.
Relatives from the vernacular
In everyday speech, the word "apple" is rare. But this word has relatives who relate not only to everyday, but even to grassroots vocabulary. The word "zenki" sounds much less worthy than "apple". You can't even say that it comes from the same Old Church Slavonic. However, this is the case. The rude colloquial expression "to gape zenki" or "goggle zenki" means "to be surprised at something to such an extent that the pupils are dilated", or "to look at something." So from the same root, both the apple, which must be protected or preserved, and the apple, meaning the extreme degree of amazement, come from.
