The words 'also', 'however', 'instead', and 'therefore' are examples of conjunctive adverbs.
Conjunctive adverbs are adverbs used to connect two clauses. Most times, they are also used to indicate a certain relationship, such as one of contrast, addition or cause and effect. In general, the position of conjunctive adverbs in a sentence can be changed; however, most times, they are enclosed in commas or in a semicolon and a comma. Besides 'also', 'however', 'instead' and 'therefore', there are other conjunctive adverbs, such as 'nonetheless', 'thus' and 'consequently'.