Archaic KJV Word
Lamb
Modern equivalent: gentle sacrificial figure
What Was Lost
The blood on the doorpost. When John said 'Behold the Lamb of God,' every hearer saw the Passover: a lamb killed, its blood painted on the door frame, the angel of death passing over. It was not a gentle image but a graphic one. In Revelation, the Lamb conquers -- the slain one turns out to be the most powerful being in the cosmos.
Closest Survivor in Modern English
Lamb of God (still used liturgically but the slaughter imagery has been sanitized away)
Peak Usage (1611)
KJV John 1:29 -- 'Behold the Lamb of God, which taketh away the sin of the world'; Revelation 5:6 -- 'A Lamb as it had been slain'
Died still used but defanged (~1900)
Hebrew seh/kebes ('lamb') and Greek amnos/arnion ('lamb') lost the Passover-sacrifice context that made John's declaration a thunderbolt. Without the visceral memory of lamb slaughter, 'Lamb of God' became a gentle title rather than a violent image.
What Replaced It
“sacrifice”
Abstract; a lamb was a specific, living creature whose blood was smeared on doorposts to prevent death
“victim”
Passive; the Lamb in Revelation is paradoxically also the Lion -- the slain one who conquers
“offering”
Ritualistic; the Passover lamb was the difference between life and death at the Exodus