Of course the Vedic/Hindu/Hare Krishna creationism you apparently accept does have a precise meaning of "day":
The Bhagavata Purana says that men and women have lived on earth for a vast period of time called the Day of Brahma, which is composed of a thousand yuga cycles. Each yuga cycle lasts 12,000 "years of the gods." And since each "year" equals 360 earth years, one yuga cycle equals 4.32 million years while a thousand yuga cycles total 4.32 billion years, summing up the Day of Brahma.
Those unfamiliar with Hindu antievolutionism might be interested to know that, although more "liberal" than fundamentalist "Young Earth" creationism in allowing for (actually insisting on) an ancient earth, it is more strict than even "strict" Christian antievolutionism in insisting on absolutely fixed species (i.e. no "micro" evolution; no evolution even "within created kinds".
The reason for this is two-fold. First because the Vedas teach that species are fixed. All (not just man) have existed here through the "Day of Brahma." IIRC correctly, the Vedas even number the "species of life". I don't remember the figure, but think it somewhere in the millions.
The second relates to the doctrine of reincarnation. In short it is the soul that evolves. In doing so in serially inhabits different "species". These species remain fixed. Hindu creationists see affirming (biological) evolution as denying (spiritual) evolution, i.e. rebirth and reincarnation.
I’m not even interested in the Hindu understanding of creation or day as it pertains to the topic of this thread. The point is that there are two world views; one is that God is the Creator, the other is that life came from nothing and evolved via random accident.
I feel much more kinship with those who accept that God created everything than with godless evolutionists, despite differences in understanding exactly how God created. No human can adequately comprehend exactly how He created or creates anyway, human minds are too limited. Other than be having such truths revealed from within.
If I wanted to discuss the ins and outs of Hindu cosmology, I’d start a thread about just that.