# in one's book

> English word · Prep_phrase

## Definitions
1. In one's opinion.
2. Used other than figuratively or idiomatically: see in, one's, book.

## Etymology
Refers to a notional book or list of one's opinions and beliefs. Slang from the mid-1900s.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/in-one-s-book