Forward means ahead or onward. A foreword is the introductory piece at the start of a book, usually written by someone other than the author. The spelling is literal: it is the word that comes before.
The core difference
A direction and a piece of a book.
- forward — ahead: step forward, forward planning. Also a football position, and to send on.
- foreword — a book's introductory section: a foreword by the editor.
The spelling is the meaning
Fore means before — as in forecast, forehead, forewarn. A foreword is literally the word placed before the book. Seeing word inside it settles the spelling permanently.
The parts of a book
A foreword is normally written by someone other than the author. A preface is by the author, about the book's creation. An introduction is by the author and part of the work itself. The three are distinct and often confused.