deuce-ace
- n the cardinal number that is the sum of one and one and one
deus ex machina
- n any active agent who appears unexpectedly to solve an insoluble difficulty
deuteranopia
- n dichromacy characterized by a lowered sensitivity to green light resulting in an inability to distinguish green and purplish-red
deuterium
- n an isotope of hydrogen which has one neutron (as opposed to zero neutrons in hydrogen)