What does “mark the beginning” mean in English?

Most learners know “mark” as a noun — a stain, or a grade. But as a verb it means “to signal that something is happening.” Adding “only the beginning” makes it stronger: we are still very early, and there is a long way to go. A scientist uses this exact phrase to describe ocean exploration — we have found a lot, but the real journey has barely started.

In the clip, a scientist explains that we have found over 250,000 ocean species — but there may be up to 2,000,000. He says these discoveries “do really mark only the beginning” — they show we are at the start of ocean exploration, not near the end. You hear this pattern in news and speeches. A journalist might write: “The new law marks only the beginning of a long reform process.” A coach might say: “Winning today marks only the beginning — we have much more work ahead.” The verb “mark” is a little formal. It fits news articles, science writing, and speeches. Speakers use it to say: yes, this is real progress, but the work is not finished.