+@node Output definitions - blueprints for contexts
+@unnumberedsubsubsec Output definitions - blueprints for contexts
+
+This section explains the relevance of output definitions when
+working with contexts. Examples for actual output definitions are
+given later (see @ref{Changing all contexts of the same type}).
+
+@cindex output definitions
+@funindex \layout
+While music written in a file may refer to context types and
+names, contexts are created only when the music is actually being
+interpreted. LilyPond interprets music under control of an
+@q{output definition} and may do so for several different output
+definitions, resulting in different output. The output definition
+relevant for printing music is specified using @code{\layout}.
+
+@funindex \midi
+A much simpler output definition used for producing Midi output is
+specified using @code{\midi}. Several other output definitions
+are used by LilyPond internally, like when using the part combiner
+(@ref{Automatic part combining}) or creating music quotes
+(@ref{Quoting other voices}).
+
+Output definitions define the relation between contexts as well as
+their respective default settings. While most changes will
+usually be made inside of a @code{\layout} block, Midi-related
+settings will only have an effect when made within a @code{\midi}
+block.
+
+@funindex autoBeaming
+Some settings affect several outputs: for example, if
+@code{autoBeaming} is turned off in some context, beams count as
+melismata for the purpose of matching music to lyrics as described
+in @ref{Automatic syllable durations}. This matching is done both
+for printed output as well as for Midi. If changes made to
+@code{autoBeaming} within a context definition of a @code{\layout}
+block are not repeated in the corresponding @code{\midi} block,
+lyrics and music will get out of sync in Midi.
+
+@seealso
+Installed Files:
+@file{ly/engraver-init.ly}.
+@file{ly/performer-init.ly}.
+