Lewis & Short

gĕnĭcŭlum, i, n. dim. [genu], a little knee, a knee.

  1. I. Lit. (ante- and postclass.): pueris in geniculis alligare serperastra, Varr. L. L. 9, § 11 Müll.: de geniculis adorare, Tert. Cor. Mil. 3: dissolutio geniculorum, Vulg. Nah. 2, 10.
  2. II. Transf., a knot or joint on the stalk of a plant, Plin. 26, 11, 71, § 117; 18, 7, 10, § 56.