From BiblePortal Wikipedia

Vine's Expository Dictionary of NT Words [1]

1: Φόβος (Strong'S #5401 — Noun Masculine — phobos — fob'-os )

"fear," is rendered "terror" in  Romans 13:3; in  2—Corinthians 5:11;  1—Peter 3:14 , AV (RV, "fear"). See Fear , No. 1.

2: Φόβητρον (Strong'S #5400 — Noun Neuter — phobetron — fob'-ay-tron )

"that which causes fright, a terror," is translated "terrors" in  Luke 21:11 , RV (AV, "fearful sights"). See Fear , A, Note. For ptoesis, See Amazement.

King James Dictionary [2]

TER'ROR, n. L. terror, from terreo, to frighten.

1. Extreme fear violent dread fright fear that agitates the body and mind.

The sword without, and terror within.  Deuteronomy 32

The terrors of God do set themselves in array against me.  Job 6

2. That which may excite dread the cause of extreme fear.

Rulers are not a terror to good works, but to the evil.  Romans 13

Those enormous terrors of the Nile.

3. In Scripture, the sudden judgments of God are called terrors. Psalms 73 4. The threatenings of wicked men, or evil apprehended from them.  1 Peter 3 5. Awful majesty, calculated to impress fear.  2 Corinthians 5 6. Death is emphatically styled the king of terrors.

Webster's Dictionary [3]

(1): ( n.) Extreme fear; fear that agitates body and mind; violent dread; fright.

(2): ( n.) That which excites dread; a cause of extreme fear.

Holman Bible Dictionary [4]

FearFear Of Isaac