Here's why:
* Langkapang means "complete" or "full" in Tagalog.
* Pangungusap means "sentence" in Tagalog.
Therefore, "langkapang pangungusap" literally means "complete sentence." A compound sentence is a sentence that combines two or more independent clauses, each of which could stand alone as a complete sentence. They are joined by conjunctions like "and", "but", "or", etc.
For example, in English:
* "The sun is shining, and the birds are singing."
This is a compound sentence because it contains two independent clauses ("The sun is shining" and "the birds are singing") joined by the conjunction "and".