Lewis & Short

oppango (obp-), pēgi, pactum, 3, v. a. [ob-pango], to fasten or fix on, to affix (anteclass. and in post-Aug. prose): ubi savium oppegit, fugit, imprinted, Plaut. Curc. 1, 1, 60: repagula, quaeex contrario oppanguntur, Paul. ex Fest. s. v. repagula, p. 281 Müll.