Thayer's Greek Lexicon

 1. of speech
  1) a word, uttered by a living voice, embodies a conception or idea
  2) what someone has said
1b1. a word
1b2. the sayings of God
1b3. decree, mandate or order
1b4. of the moral precepts given by God
1b5. Old Testament prophecy given by the prophets
1b6. what is declared, a thought, declaration, aphorism, a
weighty saying, a dictum, a maxim
  3) discourse
1c1. the act of speaking, speech
1c2. the faculty of speech, skill and practice in speaking
1c3. a kind or style of speaking
1c4. a continuous speaking discourse - instruction
  4) doctrine, teaching
  5) anything reported in speech; a narration, narrative
  6) matter under discussion, thing spoken of, affair, a matter
in dispute, case, suit at law
  7) the thing spoken of or talked about; event, deed
2. its use as respect to the MIND alone
  1) reason, the mental faculty of thinking, meditating,
reasoning, calculating
  2) account, i.e. regard, consideration
  3) account, i.e. reckoning, score
  4) account, i.e. answer or explanation in reference to judgment
  5) relation, i.e. with whom as judge we stand in relation
2e1. reason would
  6) reason, cause, ground
3. In John, denotes the essential Word of God, Jesus Christ, the
personal wisdom and power in union with God, his minister in
creation and government of the universe, the cause of all the
world's life both physical and ethical, which for the procurement
of man's salvation put on human nature in the person of Jesus the
Messiah, the second person in the Godhead, and shone forth
conspicuously from His words and deeds.

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A Greek philosopher named Heraclitus first used the term Logos around
600 B.C. to designate the divine reason or plan which coordinates a
changing universe. This word was well suited to John's purpose in
John 1.