TITLE: What does "adic" mean?
QUESTION [6 upvotes]: The word "adic" is often seen in books of algebra and number theory. I don't know what does this word mean, so I look it up in a dictionary, called Oxford Dictionary of English. But it does not appear there.
So what does this word mean just as a word, and why is it used in defining the mathematical concepts?
I am sorry if this question seems weird. English is not mother language. 
Thanks for any help.

REPLY [4 votes]: The OED Online has an entry for -adic.
The first definition relates to chemistry, while the second and third definitions relate to mathematics:
Second definition:

Math. With preceding symbol or numeral (esp. the generalized symbol p, denoting a prime number), forming adjectives designating numbers expressible as a sequence of digits in the base represented by the symbol (or as a power series in this quantity).

Third definition:

Chiefly Math. and Logic. With preceding symbol (usu. n), forming adjectives designating a function, operator, relation, etc., having the number of arguments represented by the given symbol. Cf. -ary suffix1 Additions.

(Accessed 12/4/14, 11:03am)