An open-end spanner is a common tool used for turning nuts and bolts. However, it has numerous synonyms that can be used depending on the location and context. In America, it is called a wrench while in the UK, it is a spanner. Other synonyms include crescent wrench, adjustable wrench, pipe wrench, monkey wrench, end wrench, and shift wrench. Some technicians call it a C-spanner, whereas in Canada, it's known as a torque wrench. Also, some people use the term fixed open-ended wrench for specific types. Irrespective of the synonym, this tool remains a vital part of every mechanic's and DIY enthusiast's toolbox.