also: toss · pitch · toss sweep · option pitch
Both words describe the ball traveling backward through the air to a back. Some staffs separate them by decision: a toss is called before the snap, while a pitch follows an option read.
A toss is a call. The quarterback receives the snap and immediately throws the ball backward to a back who is already running wide, and nothing about it is conditional. It gets the ball outside faster than any handoff can and it is usually paired with pullers or a reach-blocking line getting to the edge.
toss sweep, quick tosspitch, speed option, outside zoneA pitch, in most rooms, is what happens at the END of an option: the quarterback has read a defender, decided not to keep, and pitched. Same physical act, arrived at by a choice rather than by a call, and normally executed at full speed while somebody is trying to hit him.
That difference is why the words are not fully interchangeable even though many coaches use them as though they are. A toss is a play. A pitch is usually an outcome. Where a staff uses one word for both, the thing to establish is whether any pre-snap decision is involved.
option pitchtossBoth are backward passes in the rulebook's terms, which is why a dropped one is a live ball rather than an incompletion. That is the single most consequential fact about either word and it applies to both equally.