What is the type of word that may be used with a semicolon to connect independent clauses and usually serves as transition between clauses?

The type of word that may be used with a semicolon to connect independent clauses and usually serves as a transition between clauses is a conjunctive adverb.

Here are some examples of conjunctive adverbs:

* Contrast: however, nevertheless, nonetheless, still, yet, on the other hand

* Addition: also, furthermore, moreover, besides, in addition

* Cause and effect: therefore, consequently, thus, hence, accordingly

* Time: meanwhile, subsequently, then, finally, afterwards

* Exemplification: for example, for instance, namely, specifically

Example:

> The train was delayed; however, we eventually made it to the station.

In this example, "however" is a conjunctive adverb that connects the two independent clauses and shows a contrast between them.