In cell cycle, interphase is the period between two consecutive cell divisions, e.g. the interval between two mitoses (hence the name). Compared to mitosis, the interphase is generally longer in duration; it is comprised of three stages: G1, S phase, and G2. During interphase, the cell typically undergoes growth (i.e. increases in cell size) and makes a copy of the cell's DNA to prepare for the next cell division.
Word origin: inter (between) + phase (from phasis, appearance)