noun

1. a person who binds; specif., a bookbinder
2. a thing that binds or holds together; specif.,
   1. a band, cord, etc.
   2. a material that binds things together tar is a binder for gravel in paving
   3. a detachable cover with rings or clamps for holding sheets of paper together
   4. a leaf of tobacco rolled around the filler of a cigar to bind it
3. ☆ Agric.
   1. a device attached to a reaper, for tying grain in bundles
   2. a machine that both reaps and binds grain
4. Law a temporary memorandum of a contract, in effect pending execution of the final contract