As nouns the difference between adjacent and three
is that adjacent
is something that lies next to something else, especially the side of a right triangle that is neither the hypotenuse nor the opposite while three
is the digit/figure 3.
As an adjective adjacent
is lying next to, close, or contiguous; neighboring; bordering on.
As a preposition adjacent
is (us) next to; adjacent to; beside.
As a numeral three is
(cardinal) a numerical value after two and before four represented in arabic digits as ; this many dots (•••).