Oh, dude, that line from Shakespeare's Romeo and Juliet is basically like, "Hey, what's that light shining through the window?" It's Romeo being all poetic and stuff, noticing Juliet's beauty and comparing it to the rising sun. So, yeah, it's just Romeo being a total romantic, like, "Whoa, check out that light, it's like, so pretty."
Romeo Does
He didn't call the window anything. He said, "But, soft! what light through yonder window breaks? / It is the east, and Juliet is the sun." So he called the light that shone from the window "the east."
What light through yonder window breaks; it is the East and Juliet is the sun.
"Whoa, that girl is hotter than the sun!"
But, soft! What light through yonder window breaks? It is the east, and Juliet is the sun!
Romeo does not say this line to Juliet. He is hiding behind a bush in her backyard, hoping to get a glimpse of her. He knows that if he is found in her backyard he is dead meat. Suddenly, the curtains of one of the rooms part, and in the light from her room she steps out onto her balcony in her jammies. He is awestruck by her beauty, but he is not about to let on that he is there, in case she calls the security guards. To himself he says, "What light from yonder window breaks? It is the east, and Juliet is the sun." and he settles down to eavesdrop on her.
Please turn off the light. The aluminum bolt will require a light touch when snugging it up tight. What light through yonder window breaks?
But soft, what light through yonder window breaks. It is the east and Julia is the sun! -Romeo (Shakespeare's Romeo and Juliet)
Ever hear of "What light through yonder window breaks? It is the east, and Juliet is the sun."
The sunrise. "What light from yonder window breaks? It is the east, and Juliet is the sun." This is saying she is like the sun.
Shakespeare would disagree with categorizing this phrase as redneck. "What light through yonder window breaks"? Yonder is a reference to something in the distance. Down is the direction indicated. So, down yonder means something off in the distance in the direction indicated. This isn't an idiom or slang. It is literal. Even a redneck knows that.
"But soft! What light through yonder window breaks? It is the East, and Juliet is the sun." (Act 2, Scene 2, Lines 2-3)