Nummus

[4] Forms of the term nummus also appear in various scientific names and in medical jargon for coin-shaped species, structures, and disorders.

These were small, badly struck coins, weighing less than 1 gram, forming the lowest denomination of Byzantine coinage.

At this time, a new 30-nummi coin (marked with "Λ" or "XXX") was introduced, but the single follis had ceased to be struck at Constantinople.

[5][9] During the 7th century, the successive military and financial crises led to further reduction in the weight and a marked deterioration of the quality of bronze coinage; by the time of Emperor Constans II (r. 641–668), a follis weighed only 3 grams.

[5] Forms of the term nummus also appear in medical jargon and various scientific names to describe coin-shaped species, structures, and disorders:

Nummi coins of the late reign of Anastasius I : on the left a 40- nummi coin ( follis ) and on the right a 5- nummi coin ( pentanummium ).
Nummus [ dubious – discuss ] of AD 307–8
Nummus [ dubious – discuss ] of AD 317–330