open (up) daylight v. phr. especially in horse racing, to out-distance a competitor. (source: Double-Tongued Dictionary)
Further reading
Susan from Virginia Beach, Virginia, shares the phrase her mother used when the kids refused to eat: It’ll grow hair on your back teeth. This supposed motivator likely blends two older traditions: a German idiom, Haare auf den Zähnen haben...
Why do speakers of the same language have different accents? A lively new book called Why We Talk Funny offers a linguist’s look at how and why accents develop. And: If you’ve “stood up” at a wedding, were you supporting the marriage or objecting to...