furthermore; again; more and more
さらに means 'furthermore' when adding a point, and can also mean 'again' or 'more and more' depending on context.
さらに is a versatile adverb. When you are making a list of reasons or adding another point in a discussion, it works like 'furthermore' or 'moreover'. For example, after stating one advantage, you can start your next sentence with さらに to add another. This usage is common in both writing and formal speech.
When placed before a verb or an adjective, さらに can also mean 'more' or 'even more', indicating an increase in degree. For instance, さらに大きい means 'even bigger'. This is similar to もっと but a bit more formal or emphatic.
In some contexts, さらに can mean 'again' or 'further', like when something happens another time. However, this meaning is less common for learners at N3; the primary meanings are 'furthermore' and 'more and more'. Pay attention to the sentence to see which meaning fits.