Lewis & Short

ăd-allĭgo, āre, 1, v. a. (double ad, as in adaggero), to bind to, to fasten to, to attach: uncum (ad arborem), Plin. 17, 23, 35, § 211: radices, id. 20, 21, 84, § 225: vermiculos bracchio, id. 27, 10, 62, § 89.