a. (Anat.) Capable of being apposed, or applied one to another, as the thumb to the fingers of the hand; able to be brought into direct spatial opposition. Syn. -- opposable [ Webster 1913 Suppl. + WordNet 1.5 ]
a. 1. Capable of being opposed or resisted. [ 1913 Webster ]
2. Capable of being placed opposite something else; as, the thumb is opposable to the forefinger. [ 1913 Webster ]