sobrecito
sachet
sobre
envelope
+
-cito
diminutive suffix
Sobrecito means sachet and can be thought of as a small sobre0 (envelope0) with the diminutive suffix -cito1 (diminutive suffix1).
noun
- sachetA small envelope or sachet, typically containing a single serving of a productAñade un sobrecito de azúcar a tu café. // Add a sachet of sugar to your coffee.