This type of word may be used with a semicolon to connect independent clauses and usually serves as a transition between the clauses.

The correct answer is: A conjunctive adverb.

Explanation:

A conjunctive adverb is able to join two complete ideas, examples of conjunctive adverbs are:

also besides consequently finally furthermore however indeed instead likewise meanwhile otherwise nevertheless next

And more.

With conjunctive adverbs you use semicolons and not commas to connect the two clauses. Look at the following example in order for you to fully understand:

Louis' apartment does not allow dogs and cats; otherwise, she would have had one with her since she moved in there.

I think its a conjunctive adverb.