Hyperparameter optimization (including architectures) is not really meta-learning. Meta-learning, also known as "learning to learn", is more like MAML[0], RL2[1], L2RL[2], etc.

0. https://arxiv.org/abs/1703.03400

1. https://arxiv.org/abs/1611.02779

2. https://arxiv.org/abs/1611.05763