[chesley]

what was John’s meaning, if you don’t mind?

[FredZarguna]

The word used by the Gospel writer in the original Greek of John 1:5 is "κατέλαβεν." This word can mean both "understand" and "overcome".

We have some similar usages in English: we "wrestle with an idea until we pin it down," or "master a concept."

Many modern translations now translate the passage as "the light shines in the darkness, and the darkness has not overcome it." or "has not extinguished it" or "will never put it out."

See, for example: http://biblehub.com/john/1-5.htm