puzzle vs word square

puzzle and word square both are nouns.

Word	Noun	Adjective	Verb	Adverb
puzzle	Yes	No	Yes	No
word square	Yes	No	No	No

As nouns, word square is a hyponym of puzzle; that is, word square is a word with a more specific, narrower meaning than puzzle:

puzzle: a particularly baffling problem that is said to have a correct solution
word square: a puzzle where you fill a square grid with words reading the same down as across

Other hyponyms of puzzle include sudoku, acrostic, chess composition, chess problem.

puzzle (noun)	word square (noun)
a game that tests your ingenuity	a puzzle where you fill a square grid with words reading the same down as across
a particularly baffling problem that is said to have a correct solution

puzzle (verb)	word square (verb)
be a mystery or bewildering to
be uncertain about; think about without fully understanding or being able to decide