Strong's #5703: `ad (pronounced 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.
Brown-Driver-Briggs Hebrew Lexicon:
 
  ‛ad 
 
 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)
 
  Part of Speech: noun masculine
Relation: from H5710
Usage:
This word is used 48 times:
Exodus 15:18: "The LORD shall reign forever  and ever."
Numbers 24:20: "of the nations; but his latter end shall be that he perish  forever."
Numbers 24:24: "Eber, and he also shall perish  forever."
Job 19:24: "pen and lead in the rock  forever!"
Job 20:4: "Knowest thou not this of  old, since man was placed upon"
Psalms 9:5: "thou hast put out their name forever  and ever."
Psalms 9:18: "the expectation of the poor shall not perish  forever."
Psalms 10:16: "The LORD is King forever  and ever: the heathen are perished out of his land."
Psalms 19:9: "of the LORD is clean, enduring  forever: the judgments of the LORD are true and righteous"
Psalms 21:4: "it him, even length of days forever  and ever."
Psalms 21:6: "For thou hast made him most blessed  forever: thou hast made him exceeding glad with thy countenance."
Psalms 22:26: "that seek him: your heart shall live  forever."
Psalms 37:29: "the land, and dwell therein  forever."
Psalms 45:6: "Thy throne, O God, is forever  and ever: the scepter of thy kingdom is a right scepter."
Psalms 45:17: "therefore shall the people praise thee forever  and ever."
Psalms 48:14: "God is our God forever  and ever: he will be our guide even unto death."
Psalms 52:8: "in the mercy of God forever  and ever."
Psalms 61:8: "So will I sing praise unto thy name  forever, that I may daily perform my vows."
Psalms 83:17: "Let them be confounded and troubled  forever; yea, let them be put to shame, and perish:"
Psalms 89:29: "His seed also will I make  to endure forever, and his throne as the days of heaven."
Psalms 92:7: "of iniquity do flourish; it is that they shall be destroyed  forever:"
Psalms 104:5: "the foundations of the earth, that it should not be removed  forever."
Psalms 111:3: "and glorious: and his righteousness endureth  forever."
Psalms 111:8: "They stand fast  forever and ever, and are done in truth and uprightness."
Psalms 111:10: "they that do his commandments: his praise endureth  forever."
Psalms 112:3: "shall be in his house: and his righteousness endureth  forever."
Psalms 112:9: "to the poor; his righteousness endureth  forever; his horn shall be exalted with honor."
Psalms 119:44: "thy law continually forever  and ever."
Psalms 132:12: "shall also sit upon thy throne  forevermore."
Psalms 132:14: "This is my rest  forever: here will I dwell; for I have desired"
Psalms 145:1: "and I will bless thy name forever  and ever."
Psalms 145:2: "thee; and I will praise thy name forever  and ever."
Psalms 145:21: "his holy name forever  and ever."
Psalms 148:6: "He hath also established  them forever and ever: he hath made a decree which shall not pass."
Proverbs 12:19: "The lip of truth shall be established  forever: but a lying tongue is but for a moment."
Proverbs 29:14: "the poor, his throne shall be established  forever."
Isaiah 9:6: "Counselor, The mighty God,  The everlasting Father, The Prince of Peace."
Isaiah 26:4: "Trust ye in the LORD  forever: for in the LORD JEHOVAH is everlasting"
Isaiah 30:8: "that it may be for the time to come  forever and ever:"
Isaiah 45:17: "be ashamed nor confounded  world without end."
Isaiah 57:15: "the high and lofty One that inhabiteth  eternity, whose name is Holy; I dwell in the high"
Isaiah 64:9: "very sore, O LORD, neither remember iniquity  forever: behold, see,"
Isaiah 65:18: "But be ye glad and rejoice  forever in that which I"
Daniel 12:3: "and they that turn many to righteousness as the stars forever  and ever."
Amos 1:11: "all pity, and his anger did tear  perpetually, and he kept his wrath forever:"
Micah 4:5: "of the LORD our God forever  and ever."
Micah 7:18: "of his heritage? he retaineth not his anger  forever, because he delighteth"
Habakkuk 3:6: "he beheld, and drove asunder the nations;  and the everlasting mountains were scattered, the perpetual hills"