To help you avoid using the same word too repetitively, redundantly, recurrently, incessantly, etc., etc.
Why synonyms can be useful
Your writing can sound boring if you continually keep repeating the same words. When you create sentences, you can make them more interesting by using words that mean the same as the word you are speaking about. This allows you to add flavor to your writing.
In order to make language a lot more expressive and interesting you should try to vary the words you use as often as you can.
Synonyms for (noun) railroad track
Synonyms:railroad, railroad track, railwayDefinition: a line of track providing a runway for wheels Usage: he walked along the railroad track
Hypernyms:trackDefinition: a pair of parallel rails providing a runway for wheels
Definition: (adj) carefree and happy and lighthearted Synonyms: blithesome, light-hearted, lighthearted, lightsome
Usage: was loved for her blithe spirit; a merry blithesome nature; her lighthearted nature; trilling songs with a lightsome heart