Strong's #869: aphno (pronounced af'-no)

adverb from 852 (contraction); unawares, i.e. unexpectedly:--suddenly.

Thayer's Greek Lexicon:

̓́

aphnō

1) suddenly

Part of Speech: adverb

Relation: from G852 (contraction)

Usage:

This word is used 3 times:

 

Acts 2:2: "And suddenly there came a sound from heaven as of a rushing"
Acts 16:26: "And suddenly there was a great earthquake, so that the foundations"
Acts 28:6: "or fallen down dead suddenly: but after they had looked a great while,"