"The next time believers tell you that 'separation of church and state' does not appear in our founding document, tell them to stop using the word ‘trinity.’ The word ‘trinity’ appears nowhere in the bible.
Neither does Rapture, or Second Coming, or Original Sin. If they are still unfazed (or unphrased), by this, then add Omniscience, Omnipresence, Supernatural, Transcendence, Afterlife, Deity, Divinity, Theology, Monotheism, Missionary, Immaculate Conception, Christmas, Christianity, Evangelical, Fundamentalist, Methodist, Catholic, Pope, Cardinal, Catechism, Purgatory, Penance, Transubstantiation, Excommunication, Dogma, Chastity, Unpardonable Sin, Infallibility, Inerrancy, Incarnation, Epiphany, Sermon, Eucharist, the Lord's Prayer, Good Friday, Doubting Thomas, Advent, Sunday School, Dead Sea, Golden Rule, Moral, Morality, Ethics, Patriotism, Education, Atheism, Apostasy, Conservative (Liberal is in), Capital Punishment, Monogamy, Abortion, Pornography, Homosexual, Lesbian, Fairness, Logic, Republic, Democracy, Capitalism, Funeral, Decalogue, or Bible." ~ Dan Barker Via Mike Autry
Two points. A particular word may not have been in the US Constitution , but the concept was and in such a manner that future generations could interpret the concept in light of present circumstances. The amendment process was included for the same reason.