I was asked to make a comment or two here:
From another thread:
At the risk of sounding repetitive, from what we know, only some but definitely not all Mahayana traditions, and even then with very different meanings.
And for many non-Mahayana traditions, we don't know if they had such an idea or not, to be honest.
Oops, sorry, mistake. Poking around the Chattha Sangayana Tipitaka, I found this in the "other" texts:
(Nagare kapilavatthumhi sammādiṭṭhi bahujjano;
Tattha sārīrikaṃ thūpaṃ akāsi ratanāmayaṃ.
Nagare allake ramme buddhadhātu patiṭṭhiya;
Silāya muggavaṇṇāya thūpaṃ sadhātukaṃ akā.
Jano pāveyyaraṭṭhasmiṃ patiṭṭhiya sārīrikaṃ;
Silāya maṇivaṇṇāya pāveyyaṃ cetiyaṃ akā.
Tā dhātuyo ṭhapetvāna thero kassapasavhayo;
Rañño ajātasattussa adāsi dhātuyo tadā.
Gehe cūpakaraṇāni catusaṭṭhisatāni so;
Abbhantare ṭhapesi rājā sabbā tā buddhadhātuyo.
Karaṇḍāsīti saṃkiṇṇaṃ cetiyāsītilaṅkataṃ;
Gehe bahusamākiṇṇaṃ thūpārāmappamāṇakaṃ.
And also in the:
403. Katvāna agghiyaṃ tatthāti tasmiṃ cetiyapūjanaṭṭhāne tālapantīhi tālapāḷīhi cittitaṃ sobhitaṃ agghiyaṃ katvāna kāretvā ca sakaṃ cittaṃ attano cittaṃ pasādetvā cetiyaṃ pūjayuttamanti uttamaṃ buddhadhātunidhāpitaṃ cetiyaṃ pūjayinti sambandho.
So, actually, the Theravada literature does on a few very rare occasions, use the term "buddhadhātu".
My recently moved Blog, containing some of my writings on the Buddha Dhamma, as well as a number of translations from classical Buddhist texts and modern authors, liturgy, etc.: .