History: What are early reflections?

What are early reflections?

• Early reflections will impact the number and intensity of all the reflections.
  That is ratio and depth.
• Early reflections are the initial, loudest reverberations.
  Yes!
• Early reflections sets how long the reverberation will sound for.
  That is decay time.
• Early reflections is the amount of time between the original source and the start of reverberation.
  That is predelay.