broadest

As a noun terms

is .

As an adjective broadest is

(broad).

As adjectives the difference between broadest and widest

is that broadest is superlative of broad while widest is superlative of wide.

As adjectives the difference between broadest and only

is that broadest is superlative of broad while only is alone in a category.

As an adverb only is

without others or anything further; exclusively.

As a conjunction only is

under the condition that; but.

As a noun only is

only child.