A ledger or lieger (from the English dialect forms liggen or leggen, to lie or lay; in sense adapted from the Dutch substantive logger), is the principal book for recording transactions. Originally, the term referred to a large volume of Scripture/service book kept in one place in church and accessible.

According to Charles Wriothesley's Chronicle (1538):

the curates should provide a booke of the bible in Englishe, of the largest volume, to be a lidger in the same church for the parishioners to read on.

It is an application of this original meaning that is found in the commercial usage of the term for the principal book of account in a business house, the general ledger or nominal ledger (see also bookkeeping) and also in the terms purchase ledger and sales ledger.