עַד ʻad (H5703)

properly, a (peremptory) terminus, i.e. (by implication) duration, in the sense of advance or perpetuity (substantially as a noun, either with or without a preposition)

1) perpetuity, for ever, continuing future 1a) ancient (of past time) 1b) for ever (of future time) 1b1) of continuous existence 1c) for ever (of God's existence)

from עָדָה (H5710);