When using a data frame function na.rm in R, it refers to the logical parameter that tells the function whether or not to remove NA values from the calculation. It means NA remove. When na.rm is TRUE, the function skips over any NA values. However, when na.rm is FALSE, then it returns NA from the calculation being done on the entire row or column. For more details, you might want to refer to https://www.programmingr.com/tutorial/na-rm/