Other forms: authors
An author is the person who wrote a book. A best-selling author, the author of three novels, contact the author.
Writer is the broader word and covers journalism, scripts and everything else; author leans towards books and towards the legal fact of having written something. Authoress is obsolete. As a verb, to author is common in American English and disliked in British, where wrote does the job. Note authorship, co-author, and the author of a plan or a policy, meaning whoever devised it.
Too few real examples of this word to estimate which sense is commonest.
author is a creator.
Also accepted in games: writer
Latin auctor means an originator or promoter, from augere, to increase — the same verb behind augment and auction. An author was somebody who caused something to grow, which fits a founder better than a novelist.
Proto-Indo-European
*h₂ewg-
Latin
auctor
Old French
autor
Anglo-Norman
autour
Middle English
auctour
English, today
author
Built from
From Middle English auctour, from Anglo-Norman autour, from Old French autor, from Latin auctor, from augeō (“to increase, originate”). The h, also found in Middle French autheur, is unetymological as there is no h in the original Latin spelling. The OED attributes the h to contamination by authentic. a doublet of auteur.
Etymology from Wiktionary, CC BY-SA