Definition of guano. : a fertilizer containing the accumulated excrement of seabirds or bats; broadly : excrement especially of seabirds or bats.
Developmental Biology Online. Epithelial tissues come in three basic types: squamous, cuboidal and columnar. These three types of tissue are seen in either simple (only one cell layer thick) or stratified (many cells in thickness) arrangements.
squamous epithelium, the surface cells are flat; in stratified cuboidal epithelium, the surface cells are cubical or round; and in stratified columnar epithelium, surface columnar cells rest on a basal layer of cuboidal cells.