Normal pith refers to the central core of a plant stem, which is composed of soft and spongy tissue. Synonyms for the word "normal pith" include "medulla", "pith", and "marrow". The medulla is the innermost part of the stem, while the pith refers to the soft tissue that surrounds the medulla. The term "marrow" is used to describe the pith of certain plants, such as bamboo and elderberry. Normal pith is important for the structural and nutritional support of plants, and it plays a critical role in the transportation of water and nutrients between the roots and leaves.