As used in sections 42-603 and 42-617 to 42-620, the words property acquired shall mean (1) all property acquired by either husband or wife, or both, during marriage, and on and after September 7, 1947, and prior to April 20, 1949, and (2) all property acquired after April 20, 1949, (a) by exchange for, (b) by the increase of, (c) with the proceeds of, or (d) with the income from, any property defined in subdivision (1) of this section.