Strong's #1178: dekapente (pronounced dek-ap-en'-teh)
from 1176 and 4002; ten and five, i.e. fifteen:--fifteen.
Thayer's Greek Lexicon:
́
dekapente
1) fifteen
Part of Speech: noun indeclinable
Relation: from G1176 and G4002
Usage:
This word is used 3 times:
John 11:18: "nigh unto Jerusalem, about fifteen furlongs off:"
Acts 27:28: "they sounded again, and found it fifteen fathoms."
Galatians 1:18: "abode with him fifteen days."