The phrase "bottom rung" is often used to describe the lowest level of something, whether it be a job, social hierarchy, or educational ladder. To convey the same meaning, there are several synonyms that can be used interchangeably. For instance, one can use the phrase "lowest rung" or "entry-level" to describe the same concept. Alternatively, "starting point," "foundation," or "basis" can also be used. Similarly, "beginning," "commencement," or "origination" can also capture the essence of the lowest point of something. Ultimately, the choice of synonym for "bottom rung" will depend on the context and individual preference.