A star system is a group of two or more stars that are held together by gravity. Astronomers have determined that more than half of all stars are members of star systems. A star system with two stars is called a binary star. The two stars orbit each other, held together by gravity.
In "if" the title of Kipling's poem is an example of repetition because that same word is repeated throughout the poem. Repetition is when a word or phrase is repeated several times throughout the same text.
