Brown Driver Briggs

 1. to join, attach to, join together
  1) (Qal) to join, attach to
  2) (Niphal) to attach oneself
  3) (Piel) joining (participle)
  4) (Pual) to be joined together, hold oneself together
  5) (Hithpael) to join oneself
2. (Piel) to cause a scab upon, smite with scab