“Castle” From Boyd’s Bible Dictionary:
(fort). The “Tower of Antonia,” N. W. corner of the Temple at Jerusalem (Acts 21:34,37; 22:24; 23:10,16,32).
“Palace” From Boyd’s Bible Dictionary:
Royal residence
(1 Kings 7:1-12); citadel (1 Kings 16:18); fortress (2 Kings 15:25); entire royal court (Dan. 1:4); capital city (Esther 9:12). In N. T. any stately residence (Matt. 26:3; Luke 11:21).
“Castle” From Concise Bible Dictionary:
See FORTRESS.
“Palace” From Concise Bible Dictionary:
This term represents several Hebrew words, and may signify castle, fortress, the king’s residence, or any large building. Thus the expression occurs, “the palace of the king’s house” (2 Kings 15:25). Solomon built several for himself and for his wives (2 Chron. 36:19). The temple built by Solomon is also called “the palace” (1 Chron. 29:1,19). In the New Testament the palace of the high priest, αὐλἠ, signifies his court (Matt. 26:3,58,69). In Philippians 1:13 the word is πραιτὠριον, “the court of the praetor,” or governor, or perhaps “the praetorian guard,” from which Paul’s keepers were taken. Called PRAETORIUM in Mark 15:16.
Strong’s Dictionary of Hebrew Words:
Meaning:
from an unused root (meaning to be elevated); a citadel (from its height)
KJV Usage:
castle, palace. Compare 2038