No it is not. It is, however, an idiom in Hebrew, usually translated as "in the beginning".
Idiom - Back to Square One: Back to the beginning.
If someone say that something is "all Greek" to them, it means they don't understand.
The Greek word for Beginning is αρχή (archí̱)
Lexicon is not an idiom. It is a word that means either a person's vocabulary, or a dictionary (especially one for Latin, Greek, Hebrew, or Arabic).
The idiom "it's Greek to me" means that something is difficult to understand or incomprehensible. It originates from the idea that Greek language and writing were perceived as complex and foreign to non-Greek speakers.
The Pella curse tablet is a lead scroll found in Pella, the capital of ancient Macedonia in Greece and is inscribed with a curse or magic spell in a distinct Doric Greek idiom. The tablet along with other texts discovered in the area, align with the names and toponym's of the Macedonians and confirm that the locals spoke a distinct idiom of Doric Greek and that the Macedonian language was a distinct Doric Greek idiom.
Not sure if this is what you're looking for, but the "Koine" (koi-nay) Greek was the common everyday New Testament Greek language.
It is believed to be from the greek voting method using beans.
W. J. Bullick has written: 'Greek vocabulary and idiom for higher forms' -- subject(s): Dictionaries, Greek, Greek language, English language, English
Stin arhi tou hronou is a Greek equivalent of the title to the movie 'In the beginning' by Kevin Connor.
The word "idiom" comes from the Greek word "idiōma," which means "peculiarity" or "property." It entered the English language in the late 16th century from the Latin word "idioma," which also means "peculiar phraseology."
Nemisis