from The American Heritage® Dictionary of the English Language, 4th Edition
- suffix Science, art, study, or knowledge of, or skill in: photonics.
- suffix Actions, activities, or practices of: athletics.
- suffix Qualities or operations of: mechanics.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- suffix Forms nouns referring to fields of knowledge or practice.
- suffix Forms nouns relating to activities
from the GNU version of the Collaborative International Dictionary of English
- A suffix used in forming the names of certain sciences, systems, etc., as acoustics, mathematics, dynamics, statistics, politics, athletics.
from The Century Dictionary and Cyclopedia
- n. A termination of Greek origin, denoting a science or an art.
-ic + -s1 (translation of Greek -ika, from neuter pl. of -ikos, adj. suff).(American Heritage® Dictionary of the English Language, Fourth Edition)
The distinction is embodied in all the words that end in -ics: ethics, politics, esthetics, mathematics.