Implementing Input Masking and Padding in TensorFlow Keras Models | HackerNoon
Masking is a way to tell sequence-processing layers that certain timesteps in an input are missing, and thus should be skipped when processing the data.
Smashing Animations Part 2: How CSS Masking Can Add An Extra Dimension - Smashing Magazine
In CSS, masking controls visibility using a bitmap, vector, or gradient mask image. When a mask's filled pixels cover an element, its content is visible.