theophany
Concise Oxford English Dictionary © 2008 Oxford University Press:
theophany /θɪˈɒf(ə)ni/
▶noun (pl. theophanies) a visible manifestation to humankind of God or a god.
– origin OE, via eccles. L. from Gk theophaneia, from theos ‘god’ + phainein ‘to show’.
'theophany' also found in these Oxford entries:

