"Hollow" refers to an object or space that is empty or has a void inside. This can apply to various items, such as a hollow tree that has a cavity within its trunk or a hollow ball that is not solid throughout. The term can also describe feelings of emptiness or lack of substance in a situation or experience. In a broader context, "hollow" can signify a lack of depth or meaning. For example, a hollow promise is a commitment that lacks sincerity or intention. Understanding the concept of hollowness helps in recognizing both physical emptiness and emotional voids in life.