The phrase "big end" refers to the larger end of a connecting rod in an internal combustion engine. However, this phrase can also be used in a broader context, which prompts the need for synonyms that can convey the same meaning. Some of the synonyms could be "large end", "heavy end", "big side", "bigger half", or "dominant end". In terms of context, these synonyms can be used interchangeably to refer to the bigger or dominant end of an object or concept. It is essential to know these synonyms to enhance your writing and communication skills, primarily when discussing technical or mechanical aspects related to engines and machines.