After searching, I found no evidence that "fusion lashes" is a specific term or technique used in the beauty industry. However, I found some information about "hybrid lashes" which may be what was meant by "fusion lashes". Hybrid lashes are a combination of classic and volume lashes, where the classic lashes are applied individually and the volume lashes are applied in a fan shape. This technique creates a more textured and voluminous look than classic lashes alone, but is less dramatic than volume lashes alone. It is possible that "fusion lashes" is a term used by a specific lash artist or salon to describe their own unique technique, but without more information it is difficult to say for certain.