FROM STRONG’S HEBREW DICTIONARY (1890)

Strong’s Hebrew Dictionary (1890) — public domain, printed whole.

`ad ad — from 5710; 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):--eternity, ever(- lasting, -more), old, perpetually, + world without end.

see HEBREW for 05710