Aduna'tion. n.s. [from ad and unus, Lat.] The state of being united; union: a word of little use.
When, by glaciation, wood, straw, dust, and water, are supposed to be united into one lump, the cold does not cause any real union or adunation, but only hardening the aqueous parts of the liquor into ice; the other bodies, being accidentally present in that liquor, are frozen up in it, but not really united. Boyle.