Definition: The word "segi" comes from the Hebrew word for "bread." It describes a flat, rectangular piece of dough used in baking bread. Definition: A seigi (or "bread") is a flat, rectangular piece of dough commonly used for making bread. It's also called a semiglass or semigram, and its shape can vary widely depending on the type of bread used, such as sourdough or artisan breads. The word "segi" comes from the Hebrew word for "bread."