The Collaborative International Dictionary of English v.0.48:

Erd \Erd\ ([~e]rd), n. [OE. erd, eard, earth, land, country, AS.
   eard; akin to OS. ard dwelling place, OHG. art plowing,
   tillage, Icel. ["o]r[eth] crop, and to L. arare to plow, E.
   ear to plow.]
   The earth. [Prov. Eng.] --Wright.
   [1913 Webster]

   Erd shrew (Zo["o]l.), the common European shrew (Sorex
      vulgaris); the shrewmouse.
      [1913 Webster]

The Free On-line Dictionary of Computing (19 January 2023):

entity-relationship diagram
ERD

    A visual representation of an
   entity-relationship model.

   An entity-relationship diagram has a box for each entity,
   containing its properties, and lines between boxes for
   relationships.  The ends of the lines are labelled to show the
   type of relationship - one-to-one, one-to-many or
   many-to-many.

   (2019-11-03)