Ratlines are a set of lines or ropes that run up the shrouds of a ship and provide a way for sailors to climb up to the masthead. However, the word "ratlines" has a few synonyms that can be used interchangeably in some contexts. These synonyms include Jacob's ladder, shroud steps, ratlins, and futtock shrouds. Jacob's ladder is a biblical term that refers to a ladder used to climb up to heaven. Shroud steps and ratlins are both terms that refer to the individual steps or rungs that make up the ratlines. Futtock shrouds are similar to ratlines but are used to provide additional support to the mast.