multiplicity
How many times a zero repeats — controls whether a graph crosses or bounces there.
A zero c of a polynomial f has multiplicity k if (x-c)^k is the highest power of (x-c) dividing f. Odd multiplicity crosses the x-axis; even multiplicity bounces off it without crossing.
Examples
f(x) = (x+1)^3(x-2) has a zero at x=-1 with multiplicity 3 (crosses, flattening) and at x=2 with multiplicity 1 (crosses cleanly).
See also
Point table
Graph settings
Calculator