  Two decades ago "transitional disks" described spectral energy distributions
(SEDs) of T Tauri stars with small near-IR excesses, but significant mid- and
far-IR excesses. Many inferred this indicated dust-free holes in disks,
possibly cleared by planets. Recently, this term has been applied disparately
to objects whose Spitzer SEDs diverge from the expectations for a typical full
disk. Here we use irradiated accretion disk models to fit the SEDs of 15 such
disks in NGC 2068 and IC 348. One group has a "dip" in infrared emission while
the others' continuum emission decreases steadily at all wavelengths. We find
that the former have an inner disk hole or gap at intermediate radii in the
disk and we call these objects "transitional" and pre-transitional" disks,
respectively. For the latter group, we can fit these SEDs with full disk models
and find that millimeter data are necessary to break the degeneracy between
dust settling and disk mass. We suggest the term "transitional" only be applied
to objects that display evidence for a radical change in the disk's radial
structure. Using this definition, we find that transitional and
pre-transitional disks tend to have lower mass accretion rates than full disks
and that transitional disks have lower accretion rates than pre-transitional
disks. These reduced accretion rates onto the star could be linked to forming
planets. Future observations of transitional and pre-transitional disks will
allow us to better quantify the signatures of planet formation in young disks.
