The word boutique is a singular noun. The plural term is boutiques.
A boutique hotel is a smaller hotel that is not part of a huge chain, but is still top quality. They tend to have individually styled rooms.
Specialty shop may be another equivalent of 'boutique'. That's what a boutique is. Part of its appeal is due to its smaller size. Another is due to its quality merchandise. Still another is due to its fashionable offerings.
part of speech
The part of speech for this particular word is a noun.
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
The part of speech for "explicit" is an adjective.
The part of speech for "twirl" is a verb.
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "lecturer" is a noun.