Definition of retinaculum in US English:



  • 1Anatomy. A structure that holds (or appears to hold) something in place; specifically †(a) = "proligerous disc" (obsolete); (b) a ligamentous band retaining tendons in place, especially in the region of the wrist and ankle (frequently with distinguishing English or scientific Latin word or words).

  • 2An arrangement of hooks, folds, or bristles, which interlocks the fore- and hindwings of various insects during flight; specifically that on the underside of the forewing in many butterflies and moths, engaging with a frenulum on the hindwing.

  • 3In collembolans: a fused pair of appendages which hold back the furcula before releasing it for a spring.

  • 4In plants of the acanthus family: each of the hooklike projections (modified funicles) on which the seeds are attached and which aid in their ejection; a jaculator.

  • 5In orchids: the sticky gland of the rostellum to which the stalk of each of the pollinia (pollen masses) adheres; a viscidium; now rare. In asclepiads: the armlike process borne by each of the pollinia to aid pollen transfer.


Mid 17th century (in an earlier sense). From classical Latin retināculum rope that holds a thing fast, cable, tether, animal's rein, towing rope, in post-classical Latin also surgical clamp from retinēre + -culum.