A “signature” was placed on all things by God to indicate their affinities — but it was hidden, hence the search for arcane knowledge. Knowing was guessing and interpreting, not observing or demonstrating.
An attractive force between atoms, or groups of atoms, that contributes towards their forming bonds
If you have an affinity with someone or something, you feel that you are similar to them or that you know and understand them very well. He has a close affinity with the landscape he knew when he was growing up
(biology) state of relationship between organisms or groups of organisms resulting in resemblance in structure or structural parts; "in anatomical structure prehistoric man shows close affinity with modern humans"
inherent resemblance between persons or things the force attracting atoms to each other and binding them together in a molecule; "basic dyes have an affinity for wool and silk"
Relationship by marriage (as between a husband and his wife's blood relations, or between a wife and her husband's blood relations); in contradistinction to consanguinity, or relationship by blood; followed by with, to, or between
(immunology) the attraction between an antigen and an antibody a close connection marked by community of interests or similarity in nature or character; "found a natural affinity with the immigrants"; "felt a deep kinship with the other students"; "anthropology's kinship with the humanities"