The phrase "gave onto" is often misspelled as "gave unto," but the correct spelling is actually "gave on to." The pronunciation of this phrase is /ɡeɪv ɑn tuː/. The word "onto" refers to being on top of something, while "on to" refers to moving forward or becoming aware of something. So, the correct spelling of "gave on to" implies giving something to someone who will move forward with it, rather than simply placing it on top of something.
The phrase "gave onto" does not have a specific etymology as it is not a commonly used phrase or idiom. However, it appears to be derived from the verb "give" and the preposition "onto". "Give" comes from the Old English word "giefan", while "onto" is a combination of "on" and "to", which can be traced back to their respective Old English origins. The phrase "gave onto" seems to have been formed by combining these two words to express giving or bestowing something onto someone or something.