Question

Why is called headquaeters but not called headquarter?

Answer 1

Answer:

There is no particular reason. Some English words ending with an 's' are used both as singular and plural. For examples, news, measles, mumps, billiards, alms, amends, clothes, doldrums, ides, pants, etc.

Similarly, many words, such as furniture, deer, moose, audience, sheep, are spelled and pronounced the same way in both their singular and plural forms.