n. The act of superposing; a placing above or upon; a lying or being situated above or upon something else.n. In botany, same as anteposition, 2.n. Specifically, in geology, noting the relations of stratified formations to one another from the point of view of the relative time of their deposition.n. In geometry, the ideal operation of carrying one magnitude to the space occupied by another, and showing that they can be made to coincide throughout their whole extent.n. In the early church, an addition to or extension of a fast; a fast longer than the ordinary fast.