Romans 16:25-26
25 Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret** since the world began,**
26 But now is made manifest, and by the scriptures of the prophets, according to the commandment of the** everlasting** God, made known to all nations for the obedience of faith:
Aionios means: 1. Having neither beginning nor end. 2. Without end. 3. ages of the world; the times since the beginning of the worlds existence. All of these are obviously used according to the context of the passage.
Contextually verse 25 uses #3 meaning of aionios.
Contextually verse 26 uses # 1 meaning of aionios.
Matt 25:46
46 And these shall go away into everlasting punishment: but the righteous into life eternal.
Contextually there is not the slightest indication in the words of Jesus here that the punishment is not coeval with the life. Kolasis “punishment” is used in one other place in the the NT ( 1 John 4:18) and means torment. Therefore verse 46 uses #2 meaning of aionios for both.