- Biology. having only one form.
- of the same or of an essentially similar type of structure.
- (of an individual organism) showing little or no change in structure during the entire life history
- (of a species) existing or having parts that exist in only one form
- (of a chemical compound) having only one crystalline form
- Having only one form, as one crystal form.
- Having one or the same genotype, form, or structure through a series of developmental changes.