The lower quartile is a statistical term often used to describe the value that divides a data set into quarters. However, there are several synonyms for the term 'lower quartile', including first quartile, 25th percentile, and lower quartile range. These terms describe the value at which 25% of the data in a set is smaller than that value. In other words, it marks the boundary between the lowest 25% and the upper 75% of observations in a dataset. The use of different terms can depend on the context, but all these synonyms for the lower quartile are commonly used in statistical analysis and data visualization.