Glamhoth
From Tolkien Gateway
Although the Sindarin word for 'Orcs' is 'yrch', this rare but more descriptive term is also sometimes seen (although not in The Lord of the Rings or The Silmarillion).
'Glamhoth' does appear, however, in Tuor's curse in the unfinished Of Tuor and His Coming to Gondolin; "Gurth an glamhoth" - 'death to the orcs'. It is also probably seen in a shortened form in the name of Gandalf's sword, Glamdring.