Since the pattern repeats every 5 terms, we can find the remainder when 19 is divided by 5 to determine which term in the pattern the 19th term corresponds to.
19 ÷ 5 = 3 with a remainder of 4
Since there are 5 terms in the pattern, the 19th term is equivalent to the 4th term in the pattern. Therefore, the 19th term is a square.