| − | Any of various one-celled aquatic or parasitic protozoans of the genus Amoeba or related genera, having no definite form and consisting of a mass of protoplasm containing one or more nuclei surrounded by a flexible outer membrane. It moves by means of pseudopods. | + | Any of various tiny one-celled aquatic or parasitic organisms. They are classified as protozoans of the genus Amoeba or related genera. They have no solid form, instead consisting of a mass of [[protoplasm]] containing one or more [[nuclei]] surrounded by a flexible outer [[membrane]]. It moves by means of [[pseudopod]]s. |