Content-type vs. media-type?

I was just wondering if there was a difference between the "content-type"
name versus the name "media-type"; I see both used throughout the spec, and
have a hard time keeping track of which step calls for which version of the
name.
E.g. p:unescape-markup has the "content-type" option, while p:escape-markup
has the "media-type" option.
Is the difference just "media-type" is used to set a characteristic of
outgoing content, while "content-type" is a characteristic of incoming
content?
-Leif Warner