When something is teeny tiny, it is minuscule. If your mother calls your miniskirt minuscule, it probably means she wants you to change into something a bit less revealing.
In minuscule, you see the word, minus, which means lesser. The word minuscule has its roots in the Latin expression minuscula littera, a phrase used to describe the smaller letters in text. In the late 1800s, the use of the word expanded to mean very small in general — so the definition of minuscule became less minuscule.