Historical Rules · 1 July 2012
Rule 614.10
Official source text from the 1 July 2012 Rules release
An effect that causes a player to skip an event, step, phase, or turn is a replacement effect. "Skip [something]" is the same as "Instead of doing [something], do nothing." Once a step, phase, or turn has started, it can no longer be skipped -- any skip effects will wait until the next occurrence.