the GNU version of the Collaborative International Dictionary of English
adj. Pertaining to an embryo, or the initial state of any organ; embryonic.
The Century Dictionary and Cyclopedia
Of or pertaining to an embryo, or to the embryonic stage of an organism.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. of an organism prior to birth or hatching
Word Usage
"Currently, treatment is based on whether a patient's cancer is classified as alveolar or embryonal, which is determined by the appearance of a tumour sample under the microscope."