SEM - very general, chiefly linear, chiefly cross-sectional statistical modeling technique.
Factor analysis, path analysis and regression - all represent special cases of SEM.
SEM came from psychology, describing latent structures like “intelligence”.
R packages:
M-Plus - probably best software on SEM.
# ~ regressed on...
# ~~ corellated with...
# ~1 intersept
# =~ latent variable defined as ...