deciduous (adj.) Look up deciduous at
1680s, from Latin deciduus "that which falls off," from decidere "to fall off," from de- "down" (see de-) + cadere "to fall," from PIE root *kad- "to lay out, fall or make fall" (see case (n.1)). Originally with reference to leaves, petals, teeth, etc.; specific sense of "trees whose leaves fall off" (opposed to evergreen) is from 1778.