A similarity of crystalline form between substances of similar composition, as between the sulphates of barium (BaSO4) and strontium (SrSO4). It is sometimes extended to include similarity of form between substances of unlike composition, which is more properly called homœomorphism.
- Biology Similarity in form, as in organisms of different ancestry.
- Mathematics A one-to-one correspondence between the elements of two sets such that the result of an operation on elements of one set corresponds to the result of the analogous operation on their images in the other set.
- A close similarity in the crystalline structure of two or more substances of similar chemical composition.