What is the difference between "Yayin" and "Shechar"?
Rashi (citing Targum Onkelos): "Yayin" is fresh wine, whereas "Sheichar" is old wine. 1
Sifri (23): They are two names for wine.
R. Eliezer ha'Kapar, in Sifri (23): Yayin is diluted with water, and Shechar is pure wine.
Ibn Ezra: Some say that Shechar is anything that intoxicates. R. Bechayei - this is like "Yayin v'Shechar" (Vayikra 10:9) written about Aharon and his sons serving after drinking.
R. Bechayei: Yayin is old wine, and Shechar is Tirosh (grape juice).
Sifsei Chachamim: So-called because it intoxicates (from the word 'Shikor').