What is thesaurus?what do you mean by spell chek feature

Thesaurous is a book that lists words in groups of synonyms and related concepts.

A Spell Checker (or spell check) is a Software feature that checks for misspellings in a text. Spell-checking features are often embaded in software or services, such as word processor, email client, electronic dictionary, or search engine.

i will you with this is that ok

answer; i believe the correct answer is layers;