define a tissue
noun. A box of tissues. A box of tissues. The definition of tissue is group of cells, or an absorbent paper, or thin paper used for wrapping gifts.1  All of the soft joints and ligaments in your neck are an example of neck tissue.2  A Kleenex is an example of a tissue.oun. A box of tissues. A box of tissues. The definition of tissue is group of cells, or an absorbent paper, or thin paper used for wrapping gifts.