Dictionary.net

• Any cell in a sporangium or an anther wall which by hygroscopic contraction helps to open them.

1920 - A dictionary of scientific terms.
By Henderson, I. F.; Henderson, W. D.

• A general term to designate the cells forming a contractile tissue, such as white blood corpuscles and other ameboid cells, ciliated epithelium, and muscular tissue.

1916 - Appleton's medical dictionary
By Smith Ely Jelliffe