(追記) (追記ここまで)
Compression
Contraction
A transformation in which a figure grows smaller. Compressions may be with respect to a point (compression of a geometric figure) or with respect to the axis of a graph (compression of a graph).
Note: Some high school textbooks erroneously use the word dilation to refer to all transformations in which the figure changes size, whether the figure becomes larger or smaller. Compression (or contraction) refers to transformations in which the figure becomes smaller. Dilation properly refers only to transformations in which the figure grows larger. Unfortunately the English language has no word that refers collectively to both stretching and shrinking.