ic

1. forming adjectives such as Islamic, terrific.
2. forming nouns such as lyric, mechanic.
3. denoting a particular form or instance of a noun ending in -ics.

   aesthetic

   dietetic

   tactic

4. denoting an element in a higher valency.

   ferric

   sulphuric

from French -ique, Latin -icus, or Greek -ikos .

1. integrated circuit.
2. internal combustion.

   the IC engine

1. (especially in military contexts) in charge of.

   the Quartermaster General is i/c rations

2. in command.

   2 i/c = second in command