Deflation is a decline in the speed of money.
Inflation is an increase in the speed of money.
Deflation in a credit-based based economy means a decrease in private credit availability, even if cash has increased.
We have deflation because less money is moving, e.g. fewer homes sold at lower prices than before.
So rents can go up in price due to less demand for purchasing housing and you still have deflation.
It’s not about prices per se, but about the overall speed of money and growth/shrinkage of credit availability.