Definition: A shape for a biological structure that approximates an ellipsoid. (eg: for a cell, see Table 1, Olenina, I., Hajdu, S., Edler, L., Andersson, A., Wasmund, N., Busch, S., Göbel, J., Gromisz, S., Huseby, S., Huttunen, M., Jaanus, A., Kokkonen, P., Ledaine, I. and Niemkiewicz, E. 2006. Biovolumes and size-classes of phytoplankton in the Baltic Sea. HELCOM Balt.Sea Environ. Proc. No. 106, 144pp.)
Definition: A landform that extends above the surrounding terrain in a limited area. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit and a local relief of more than 300m.