extension ladder vs ladder

extension ladder and ladder both are nouns.

Word	Noun	Adjective	Verb	Adverb
extension ladder	Yes	No	No	No
ladder	Yes	No	Yes	No

As nouns, ladder is a hypernym of extension ladder; that is, ladder is a word with a broader meaning than extension ladder:

extension ladder: a ladder whose length can be extended
ladder: steps consisting of two parallel members connected by rungs; for climbing up or down

extension ladder (noun)	ladder (noun)
a ladder whose length can be extended	steps consisting of two parallel members connected by rungs; for climbing up or down
	a row of unravelled stitches
	ascending stages by which somebody or something can progress

extension ladder (verb)	ladder (verb)
	come unraveled or undone as if by snagging