The Pali word for 'cause' is 'hetu', which means direct cause, such as oxygen & hydrogen are the cause of water. An example of the use of 'hetu' is SN 22.82, which says the four elements of earth, wind, fire & water are the cause of the physical body aggregate:
The four great elements, bhikkhu, are the cause and condition for the manifestation of the form aggregate.
Cattāro kho, bhikkhu, mahābhūtā hetu, cattāro mahābhūtā paccayo rūpakkhandhassa paññāpanāya.
SN 12.2 uses the word 'paccaya', which means "resting on, falling back on, foundational". For example, AN 10.61 says ignorance has no preceding cause (hetu) yet also says the five hindrances are a condition (paccaya) for the maintenance of ignorance. AN 10.61 clearly shows the words 'cause' ('hetu') and 'condition' ('paccaya') are not synonymous because the five hindrances are not the cause of ignorance. If the five hindrances were the cause of ignorance then when the five hindrances are absent during the 1st jhana or even lesser concentration, full enlightenment would occur via the absence of ignorance.
SN 12.23 uses the word 'upanisā', which appears to be from 'upa' ('close') and 'nissaya' ('support'). It appears 'upanisā' and 'paccaya' are synonymous.
In summary, ignorance is obviously not the cause of the three sankhara (breathing, thought and perception & feeling) in Dependent Origination because the three sankhara continue to exist in a Buddha. Similarly , the three sankhara are not the cause of consciousness because a Buddha remains consciousness depsite having no ignorance; just as consciousness is not the cause of nama-rupa because consciousness cannot cause the existence of 'rupa' ('physical matter').
In Dependent Origination, ignorance is merely something the pollutes or taints the sankhara, consciousness, mind-body, sense bases & sense contact. However, it can be said ignorance causes (hetu) craving, attachment, ego-becoming, ego-birth, ego-death, dukkha and any other unwholesome mental state.
In conclusion, it appears paccaya (condition) is a general and flexible word that can accommodate both a condition and a cause. This appears why the words 'paccaya' and 'upanisā' are used in Dependent Origination rather than the rigid 'hetu' ('cause').