Morph prefix is a term used in biology to describe the location of an organism or structure relative to another. The prefixes ecto and endo are used to indicate whether something is located on the outside or inside of another structure. Ecto is derived from the Greek word ektos, meaning outside, while endo is derived from the Greek word endon, meaning within. Together, these two prefixes can be used to describe the position of an organism or structure relative to another.