The word "一把手" is formed by sequentially combining the character "一" meaning "one", the character "把" which functions as a measure word often associated with handling or gripping, and the character "手" meaning "hand". Literally, this constructs the phrase "one hand", but through conventional usage, it has adopted a figurative meaning referring to the primary person in charge or the top leader in a group, derived from the concept of being the first or foremost handler of affairs.