The lower limits or thresholds, especially related to financial or budgetary constraints.
Subceilings are like rules about how much money can be used, and they are usually strict.
Examples:
The company has subceilings for each department's spending.
We need to stay within the subceilings for our project budget.
The subceilings for travel expenses are very low.
The subceilings for snack spending are so low, it's like they don't want us to eat at all.
The subceilings for the party budget are so high, we can have a big celebration!
The subceilings for toy buying are very strict, but I still want a new toy.