- An artificial ridge set crosswise into the surface of a street, parking lot, or driveway to make the operators of vehicles decrease speed.缓速块：交错分布于街道、停车场或车道的路面上的人工突起部，用来使机动车驾驶者减低速
- ultimo
- ultra
- ultra-
- ultrabasic
- ultracentrifuge
- ultraconservative
- ultradian
- ultrafiche
- ultrafiltration
- ultrahigh
- ultrahigh frequency
- ultraism
- ultraisms
- ultraliberal
- ultralight
- ultralow frequency
- ultramafic
- ultramarathon
- ultramarine
- ultramarine blue
- ultramicrofiche
- ultramicrometer
- ultramicroscope
- ultramicroscopic
- ultramicrotome