How should I understand "a hundred years on" in this sentence?

I learned the following sentence from The Economist.

A hundred years on, superconductors have found widespread use in just one technology, magnetic resonace imaging, which lets doctors peer inside patients' bodies.

How should I understand the phrase "a hundred years on"? There are so many meanings of the preposition "on" in the dictionary. What kind of dictionary should I refer to when I have similar problems?

Solution 1:

A hundred years on means a hundred years later; i.e. a hundred years after superconductivity was first observed.

I looked in the Oxford Advanced Learner's Dictionary, the Oxford English Dictionary that's built into my Kindle and en.wiktionary.org, and the best I could find was:

further forward; in an advanced state: I'll see you later on; time's getting on

-- Oxford English Dictionary

I agree that's not very helpful when you're trying to make sense of the phrase a hundred years on when there are so many other possible meanings. You have to rely on context. Look at the headline of the article you were reading:

Superconductors: A century after their discovery, superconductors are finally moving beyond scientific and medical uses and into power grids

or the preceding paragraph:

exactly a century ago, he ... discovered superconductivity.

I should also mention that the The Economist is notable for it's sophisticated-yet-playful use of English (plus the occasional foreign word, just to make things interesting). I consider The Economist the ultimate challenge for learners of English. I'm sure there are lots of words and usages in The Economist you won't find in most dictionaries.

Solution 2:

On functions as an adverb rather than a preposition in the sentence since it is NOT followed by a direct object.

Here is the 35th meaning of on from dictionary.com.

forward, onward, or along, as in any course or process: further on.

Solution 3:

Read it as: A hundred years later.