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Vine's Expository Dictionary of NT Words [1]

1: Ἐπεί (Strong'S #1893 — Conjunction — epei — ep-i' )

a conjunction, when used of cause, meaning "since," "otherwise," "for then," "because;" in an ellipsis, "else," as in  1—Corinthians 7:14 , where the ellipsis would be "if the unbelieving husband were not sanctified in the wife, your children would be unclean;" cp.  Romans 11:6,22;  1—Corinthians 5:10;  Hebrews 9:26 . Sometimes it introduces a question, as in  Romans 3:6;  1 . Cor. 14:16; 15:29;  Hebrews 10:2 . It is translated "else" in  1—Corinthians 14:16 and in the RV in   Hebrews 9:26;  10:2 , for AV, "for then."

King James Dictionary [2]

ELSE, a. or pron. els. L. alius, alias. See Alien.

Other one or something beside. Who else is coming? What else shall I give? Do you expect any thing else? This word, if considered to be an adjective or pronoun, never precedes its noun,but always follows it.

ELSE, adv. els. Otherwise in the other case if the fact were different. Thou desirest not sacrifice, else would I give it that is, if thou didst desire sacrifice, I would give it.  Psalms 5:16 Repent, or else I will come to thee quickly that is, repent, or if thou shouldst not repent, if the case or fact should be different, I will come to thee quickly.  Revelation 2:5 .

1. Beside except that mentioned as, no where else.

Webster's Dictionary [3]

(1): ( adv. & conj.) Besides; except that mentioned; in addition; as, nowhere else; no one else.

(2): ( adv. & conj.) Otherwise; in the other, or the contrary, case; if the facts were different.

(3): ( a. & pron.) Other; one or something beside; as, Who else is coming? What else shall I give? Do you expect anything else?