For questions related to the deep Q-network (DQN), which is a deep neural network (e.g. a convolutional neural network) trained with a variant of Q-learning. The expression was coined in the paper "Playing Atari with Deep Reinforcement Learning" (2013) by Google's DeepMind.
For more info, have a look at the paper Playing Atari with Deep Reinforcement Learning (2013), by V. Mnih et al. See also Human-level control through Deep Reinforcement Learning (2015), by V. Mnih et al., and Implementing the Deep Q-Network (2017) by M. Roderick et al.