1. Of a song, number-one on Billboard Magazine's charting system and still gaining in terms of sales or playtime on the radio. (The "bullet" in this phrase refers to an icon placed next to a song that makes rapid progress in the charts.) And now, number one with a bullet, here's the new hit single from Taylor Swift!

2. By extension, far better than anything/anyone else; having rapidly become the best, most authoritative, or most dominant among others in a certain group. The findings of this remarkable study truly mark Dr. Colvin as number one with a bullet in her field. The tech giant started of humbly, but it became number one with a bullet in the mid-'90s.