In MN140 and DN33 the term is used in the sense of foundation. More specifically, the Buddha tells us of four foundations:
‘This person has four foundations.’
That’s what I said, but why did I say it?
The foundations of wisdom, truth, generosity, and peace.
‘This person has four foundations.’
That’s what I said, and this is why I said it.‘Caturādhiṭṭhāno ayaṃ, bhikkhu, puriso’ti—iti kho panetaṃ vuttaṃ.
Kiñcetaṃ paṭicca vuttaṃ?
Paññādhiṭṭhāno, saccādhiṭṭhāno, cāgādhiṭṭhāno, upasamādhiṭṭhāno.
‘Caturādhiṭṭhāno ayaṃ, bhikkhu, puriso’ti—iti yaṃ taṃ vuttaṃ idametaṃ paṭicca vuttaṃ.