I tend to simplify things when discussing engorgement with the mom, usually
while she has a full blown case of it.  Primary engorgement comes day 3-5
when the milk comes in, it can be a firm fullness to the breast or it can be
overwhelming, depending on the mother's situation and should be resolved in
1-2, sometimes 3, days, depending on how the mother handles her engorgement.
A secondary engorgement is the firmness that is noticeable to the mother for
the 1st 6-8 weeks and then goes away almost overnight, leaving a soft
breast.  I use as an example how my mother and aunt nursed their babies for
the 1st six weeks until their milk went away, most moms have heard this sort
of story from their mother or grandmother.  These may not be correct medical
definitions, but it's an easy way to help moms understand the difference.
    Jacie in beautiful, sunny, blue skies Albuquerque, New Mexico, with
absolutely NO SNOW on the slopes!