According to the Greek-English Lexicon of the New Testament and Other
Early Christian Literature Third Edition (Copyright © 2000 by The
University of Chicago Press) the Greek word 'angelos' (actually spelt
aggelos in Greek but the first 'g' is pronounced as an 'n') means 'a human
messenger serving as an envoy, an envoy, one who is sent' in the following
verses:
a. sent by humans: in his earthly ministry Jesus Lk 9:52; of John the
Baptist?s disciples 7:24.
b. sent by God: of John the Baptist as forerunner Mt 11:10; Mk 1:2; Lk
7:27.
Everywhere else it means 'a transcendent power who carries out various
missions or tasks, messenger, angel' and is used:
a. as messengers of God, angels
b. intermediate beings gener., w. no ref. to their relation to God
c. evil spirits