Hi Thief. Good morning. The term is in Hebrew e'heyeh aser' e'heyeh translated usually as I AM WHO I AM, or I AM. This is a poetic expression of Yahweh's very nature. We could get in a discussion of the meaning of the name Yahweh but it is related to meaning existence which is why it's such a beautiful name because those who come to Him want to exist (in eternal life). You alluded to Exodus 3:14. In the next verse, Exodus 3:15, Yahweh says his Name: "15 And Elohim said moreover unto Moses, Thus shalt thou say unto the children of Israel, Yahweh, the Elohim of your fathers, the Elohim of Abraham, the Elohim of Isaac, and the Elohim of Jacob, hath sent me unto you: this is my name for ever, and this is my memorial unto all generations."
Notice, he says "this is my memorial unto all generations". You might want to look up the word memorial in a dictionary when you get the time. I'm sure you'll find it enlightening.