The word "rapture" is not found in the bible, just as "trinity" or "bible" is not there, but the teaching is there.
As for rapture concept in the OT, let's see Isaiah 26:19-21:
19 Thy dead men shall live, together with my dead body shall they arise. Awake and sing, ye that dwell in dust: for thy dew is as the dew of herbs, and the earth shall cast out the dead. The first thing that will occur is the resurrection of the dead in Christ.
20 Come, my people, enter thou into thy chambers, and shut thy doors about thee: hide thyself as it were for a little moment, until the indignation be overpast. Then rapture. "Come, my people" indicates the catching up of saints.
21 For, behold, the LORD cometh out of his place to punish the inhabitants of the earth for their iniquity: the earth also shall disclose her blood, and shall no more cover her slain.
Isaiah 26:19-21 seems to coincide with 1 Thess 4:16-17:
16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Resurrection of the dead in Christ.
17 Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord. Rapture - catching up of saints.