threshold
nounUK /ˈθreʃ.həʊld/
US /ˈθreʃ.hoʊld/
The flat part at the bottom of a door that you step over.
She wiped her feet on the mat at the threshold before going inside.
OTHER MEANINGS
2. The point at which something starts or changes.
The sound was so quiet it was below the threshold of hearing.
3. The smallest amount needed for something to happen.
You need to earn above a certain threshold to pay that tax.
4. The level at which something begins to be felt or noticed.
Her pain threshold is high, so she rarely complains.