bollard vs riding bitt

bollard and riding bitt both are nouns.

Word	Noun	Adjective	Verb	Adverb
bollard	Yes	No	No	No
riding bitt	Yes	No	No	No

As nouns, riding bitt is a hyponym of bollard; that is, riding bitt is a word with a more specific, narrower meaning than bollard:

bollard: a strong post (as on a wharf or quay or ship for attaching mooring lines)
riding bitt: one of the large bitts used to secure the cable of a dropped anchor

bollard (noun)	riding bitt (noun)
a strong post (as on a wharf or quay or ship for attaching mooring lines)	one of the large bitts used to secure the cable of a dropped anchor