Before the development of the electric guitar and the use of synthetic materials , a guitar was defined as being an instrument having `` a long , fretted neck , flat wooden soundboard , ribs , and a flat back , most often with incurved sides '' .
A guitar was described by Dr. Michael Kasha as an instrument that had `` a long , fretted neck , flat wooden soundboard , ribs , and a flat back , most often with incurved sides '' .