I ran across this quote today in my reading and thought it–along with the entire section–was helpful.
The inerrancy of Scripture means that Scripture in the original manuscripts does not affirm anything that is contrary to fact.
This definition focuses on the question of truthfulness and falsehood in the language of Scripture. The definition in simple terms just means that the Bible always tells the truth and that it always tells the truth concerning everything it talks about. This definition does not mean that the Bible tells us every fact there is to know about any one subject, but it affirms that what it does say about any subject is true.
[Wayne A. Grudem, Systematic Theology : An Introduction to Biblical Doctrine (Leicester, England; Grand Rapids, Mich.: Inter-Varsity Press; Zondervan Pub. House, 1994), 90-91.]