“Even though it always holds true, people couldn't comprehend the Lógos, not even after they've been told about it." -- Heraclitus, 450 BC (DK B1)
“In it was life, and the life was the light of men. And the light in the darkness shined; and the darkness comprehended it not. -- John 1:4-5 (KJV)

Things get lost in translation. Lógos does not have its equivalent in modern languages (and Latin was already too modern) so it became "the word" in Gospels. A placeholder, maybe? But then they couldn't think of anything, so it stayed. In yet another context, namely Euclid explaining geometrical proportions, lógos was translated as "ratio" — hence the word "rational". See what I mean?

I bet they tried to do Heraclitus as well, but couldn't get past "I told you so."