a bar of iron bent into the shape of a U, fitted with a screw thread and nut at each end.
Origin of U bolt
First recorded in 1880–85
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a metal bar bent into the shape of a U and threaded at both ends to receive securing nuts: used to secure leaf springs, ring bolts, shackles, etc
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012