一個句子不懂,求解!!!

Pennsylvania Avenue is one of Washington's main thoroughfares — a broad road, six miles long, that cuts diagonally through the city, beginning in the southeast, at the intersection with Southern Avenue, and heading northwest. It was one of the city's first streets, mentioned as early as 1791 in a... 顯示更多 Pennsylvania Avenue is one of Washington's main thoroughfares — a broad road, six miles long, that cuts diagonally through the city, beginning in the southeast, at the intersection with Southern Avenue, and heading northwest. It was one of the city's first streets, mentioned as early as 1791 in a letter written by Thomas Jefferson. In the years since it was laid out, Pennsylvania has unofficially earned the title of America's Main Street — "a nod to the line "it runs from the Capitol to the White House

這是出自
http://www.theguardian.com/artanddesign/2014/apr/13/walking-down-main-street-usa
的一篇新聞
倒數第二行 a nod to the line不知道是什麼意思???

希望各位能幫小弟解答,非常感謝:)
更新: 是倒數第一行才對!!!
3 個解答 3