From BiblePortal Wikipedia

Vine's Expository Dictionary of NT Words [1]

1: Ἐντός (Strong'S #1787 — Preposition — entos — en-tos' )

an adverb denoting "within," or "among," is once used with the article, as a noun, of "the inside (of the cup and of the platter),"  Matthew 23:26 , RV (AV, "that which is within etc."); elsewhere,  Luke 17:21 . See Within.

2: Ἔσωθεν (Strong'S #2081 — Adverb — esothen — es'-o-then )

an adverb denoting "from within," or "within," is used with the article, as a noun, of the inner being, the secret intents of the heart, which, the Lord declared, God made, as well as the visible physical frame,  Luke 11:40 . In  Luke 11:39 , it is rendered "inward part." See Inward , Within.

Webster's Dictionary [2]

(1): ( n.) An inside passenger of a coach or carriage, as distinguished from one upon the outside.

(2): ( a.) Being within; included or inclosed in anything; contained; interior; internal; as, the inside passengers of a stagecoach; inside decoration.

(3): ( n.) The part within; interior or internal portion; content.

(4): ( a.) Adapted to the interior.

(5): ( adv.) Within the sides of; in the interior; contained within; as, inside a house, book, bottle, etc.

(6): ( n.) The inward parts; entrails; bowels; hence, that which is within; private thoughts and feelings.

King James Dictionary [3]

IN'SIDE, n. in and side. The interior part of a thing internal part opposed to outside as the inside of a church the inside of a letter.