The root of logic and every -ology. In Greek it meant word, reason, ratio, argument, account, and the principle holding the cosmos together, all at once.
Documented
The semantic range is documented and unmanageable
Logos, from lego, to gather, recount, say, spans: word, speech, story, reason, proportion, ratio, account, principle. Heraclitus made it the ordering structure of the cosmos. The Stoics made it the rational fire running through matter, logos spermatikos, the seed-bearing reason. Philo of Alexandria bridged it into Jewish thought. The Septuagint used it for God's utterance. By John 1:1, all of that was already loaded into the word.
Assessment: Fully documented in the lexica and the primary texts. The English 'Word' is a defensible choice and an enormous compression, and both facts are on the record.
Stories
The translators kept choosing smaller
The story of the word in translation: Latin ratio or verbum, chose verbum, the word. English followed. Each stage cut the meaning down to the speakable part, and the philosophy evaporated, until generations of readers met 'the Word' with no idea it once meant the logic of the universe.
Assessment: Documented as translation history. The compression pattern matches the Christos card next door: translation keeps softening the technical into the devotional, and the original senses stay legible only in the lexicon.
Interesting claims
The sentence is a physics claim wearing a scripture costume
The strong reading: John 1:1 is not poetry, it is a cosmological statement, in the beginning was the rational structure, and the structure was with God and was God, the Philo-Stoic logos doctrine inserted into the gospel's first line. On this reading, the verse is Greek philosophy smuggled into scripture, and 'the Word' is the smuggler's costume.
Assessment: The Philo connection is standard Johannine scholarship, genuinely contested in degree. The smuggling framing is the interesting claim: mainstream scholars agree the verse participates in logos philosophy, and disagree about everything else. The compression, at least, is undeniable.
Sources and further reading
Heraclitus, fragment DK 22 B1, the logos men fail to comprehend
Gospel of John 1:1
Philo of Alexandria, De Opificio Mundi 24-25
Worth asking
Heraclitus said the logos governs all things but men fail to notice. If the word means the structure of reality and the sentence about it at the same time, which one did the gospel mean?