cot vs baby's bed

cot and baby's bed both are nouns.

Word	Noun	Adjective	Verb	Adverb
cot	Yes	No	No	No
baby's bed	Yes	No	No	No

As nouns, baby's bed is a hypernym of cot; that is, baby's bed is a word with a broader meaning than cot:

cot: baby bed with high sides made of slats
baby's bed: a small bed for babies; enclosed by sides to prevent the baby from falling

Other hypernyms of cot include baby bed.

cot (noun)	baby's bed (noun)
a small bed that folds up for storage or transport	a small bed for babies; enclosed by sides to prevent the baby from falling
baby bed with high sides made of slats
a sheath worn to protect a finger