threshold

noun

• The point of entry or beginning.
• The minimum value of a signal that produces a detectable output.
• A strip of wood, metal, or stone forming the bottom of a doorway and crossed in entering a house or room.
• Degree or level at which something begins
• The magnitude or intensity that must be exceeded for a certain reaction, phenomenon, result, or condition to occur or be manifested.
• The level of stimulation required to trigger a neural impulse.