[[1]] is a Subordinating conjunction.

 

 

The word 'Though' is a Subordinating conjunction. All clauses which introduced by Subordinating conjunctions are Subordinate clauses.Hence, A conjunction that joins a Dependent / Subordinate clause to the main / coordinate clause of a complex sentence, is called a Subordinating Conjunction.

Example : 

Subordinating Conjunctions : After, Although, As ,Before, If etc.