watchband vs watchstrap

watchband and watchstrap both are nouns.

Word	Noun	Adjective	Verb	Adverb
watchband	Yes	No	No	No
watchstrap	Yes	No	No	No

As nouns, watchband and watchstrap are synonyms defined as:

watchband and watchstrap: a band of cloth or leather or metal links attached to a wristwatch and wrapped around the wrist

Other synonyms of watchband include bracelet, watch bracelet, wristband.

watchband (noun)	watchstrap (noun)
a band of cloth or leather or metal links attached to a wristwatch and wrapped around the wrist	a band of cloth or leather or metal links attached to a wristwatch and wrapped around the wrist