Answer: Dispensationalism is a system of theology that has two primary distinctives. 1) A consistently literal interpretation of Scripture, especially Bible prophecy. 2) A distinction between Israel and the church in God's program.
Dispensationalists claim that their principle of hermeneutics is that of literal interpretation, which means giving each word the meaning it would commonly have in everyday usage. Symbols, figures of speech and types are all interpreted plainly in this method, and this is in no way contrary to literal interpretation. Even symbols and figurative sayings have literal meanings behind them.
There are at least three reasons why this is the best way to view Scripture. First, philosophically, the purpose of language itself seems to require that we interpret it literally. Language was given by God for the purpose of being able to communicate with man. The second reason is biblical. Every prophecy about Jesus Christ in the Old Testament was fulfilled literally. Jesus' birth, Jesus' ministry, Jesus' death, and Jesus' resurrection all occurred exactly and literally as the Old Testament predicted. There is no non-literal fulfillment of these prophecies in the New Testament. This argues strongly for the literal method. If literal interpretation is not used in studying the Scriptures, there is no objective standard by which to understand the Bible. Each and every person would be able to interpret the Bible as he saw fit. Biblical interpretation would devolve into “what this passage says to me...” instead of “the Bible says...” Sadly, this is already the case in much of what is called biblical interpretation today.
Dispensational theology teaches that there are two distinct peoples of God: Israel and the church. Dispensationalists believe that salvation has always been by faith—in God in the Old Testament and specifically in God the Son in the New Testament. Dispensationalists hold that the church has not replaced Israel in God’s program and the Old Testament promises to Israel have not been transferred to the church. They believe that the promises God made to Israel (for land, many descendants, and blessings) in the Old Testament will be ultimately fulfilled in the 1000-year period spoken of in Revelation chapter 20. Dispensationalists believe that just as God is in this age focusing His attention on the church, He will again in the future focus His attention on Israel (Romans 9-11).
Using this system as a basis, dispensationalists understand the Bible to be organized into seven dispensations: Innocence (Genesis 1:1–3:7), conscience (Genesis 3:8–8:22), human government (Genesis 9:1–11:32), promise (Genesis 12:1–Exodus 19:25), law (Exodus 20:1–Acts 2:4), grace (Acts 2:4–Revelation 20:3), and the millennial kingdom (Revelation 20:4-6). Again, these dispensations are not paths to salvation, but manners in which God relates to man. Dispensationalism, as a system, results in a premillennial interpretation of Christ’s second coming and usually a pretribulational interpretation of the rapture. To summarize, dispensationalism is a theological system that emphasizes the literal interpretation of Bible prophecy, recognizes a clear distinction between Israel and the church, and organizes the Bible into the different dispensations it presents.
Recommended Resource: Dispensationalism by Charles Ryrie.