1: μυστήριον
(Strong's #3466 — Noun Neuter — musterion — moos-tay'-ree-on )

primarily that which is known to the mustes, "the initiated" (from mueo, "to initiate into the mysteries;" cp. Philippians 4:12 , mueomai, "I have learned the secret," RV). In the NT it denotes, not the mysterious (as with the Eng. word), but that which, being outside the range of unassisted natural apprehension, can be made known only by Divine revelation, and is made known in a manner and at a time appointed by God, and to those only who are illumined by His Spirit. In the ordinary sense a "mystery" implies knowledge withheld; its Scriptual significance is truth revealed. Hence the terms especially associated with the subject are "made known," "manifested," "revealed," "preached," "understand," "dispensation." The definition given above may be best illustrated by the following passage: "the mystery which hath been hid from all ages and generations: but now hath it been manifested to His saints" (Colossians 1:26 , RV). "It is used of:

1—Corinthians 13:214:2 1—Timothy 3:91—Corinthians 2:6-16 Colossians 2:24:31—Corinthians 2:1 1—Timothy 3:16Ephesians 1:9 Revelation 10:7Romans 16:25Ephesians 6:19Ephesians 5:32 Colossians 1:271—Corinthians 15:51Matthew 13:11Mark 4:11Romans 11:252—Thessalonians 2:7Revelation 17:5,7Ephesians 2:2Revelation 1:20Ephesians 3:91—Corinthians 4:1