Translations such as drop repeats and reflections relate to the details, textures or images that make up a pattern. Tessellations refer to the geometric plan of the pattern as a whole.
Knitwear Design 101: Tessellations and surface pattern design
Knitwear Design 101: Drop repeats and surface pattern design
The drop repeat is the most widely used method of tessellation symmetry in knitting and crochet. It can occur along a vertical axis – when most textile books will refer to it as a ‘drop’ repeat – or a horizontal axis, when it can also be referred to as a brick repeat.