Pitch

the tuning of tone

A pitch is the key a production is played in: the same fixed events, tuned to one dominant tone. It is chosen for a run, not written into the events; a different pitch is a different production of the same tale.

Tenor

The dominant register the run is tuned to, the key its events are played in.

Undertow

The counter-current beneath the tenor, the pull against it that keeps the tone from going flat.

Nerve

What the pitch presses in the audience, the feeling it is built to strike.

Echo

What the pitch leaves once the run is over, the aftertaste that lingers.

Tenor and Nerve are the tone and its target; Undertow and Echo are what keeps it honest and what it leaves behind. A pitch succeeds when the same events, tuned to it, strike a feeling the bare account never could, without changing what happens.