A salvo is a collection of spaceships (usually gliders) that are all coming from the same direction. A salvo is generally aimed at a target to produce a specific reaction -- for example, in a sliding-block memory or a slide gun, a salvo might move a block or other still life a step closer to the salvo source, or a step farther away. Or two or more salvos may collide with each other to construct a complex object.
A slow salvo is a salvo in which the spaceships are far enough apart that any collision reaction affecting the nth spaceship has settled down by the time the (n+1)st spaceship arrives.
A P1 slow salvo is a slow salvo in which the intermediate settled-down stages are all period 1 (i.e., stable.) It is conjectured that any glider-constructible object can be produced by a P1 slow salvo aimed at a single block or other small still life -- though the number of gliders needed may be very large. Conversely, a P2 slow salvo
A monochromatic slow salvo is a slow salvo which contains only gliders of a single color. For example, half-baked knightships reconstruct their glider seed constellations using monochromatic slow salvos.