In the early 20th century, the word significant had one dominant meaning. If you said that it signified or showed something – that it had or conveyed a meaning. When R.A. Fisher said that a result was significant, he meant that the data showed some difference from the null hypothesis. In other words, we were able to learn something from those data. This sense of the word significant has persisted in the scientific literature. When discussing data, a statistically significant result means that a null hypothesis has been rejected.