Complex sentence: In Western symphonic music the flat faced gongs are generally referred to as tam-tams to distinguish them from their bossed counterparts, and the term "gong" is reserved to the bossed type only.
Split into simpler sentences: In Western symphonic music, the flat faced gongs are generally referred to as tam-tams to distinguish them from their bossed counterparts. Here, the term "gong" is reserved for the bossed type only.