What is the difference between ac (or atque) and et? And how do I know when to use atque instead of just ac?

It seems that ac "binds more tightly" than et. Is this true? Or is the difference between ac (or atque) and et the conjunctive analogue of the difference between vel and aut?

2 Answers 2


Atque, according to L&S, means

a copulative particle, and also, and besides, and even, and

According to Bennett's New Latin Grammar ch. 6 §"Coordinate Conjunctions", "atque is used before vowels and consonants; ac never before vowels, and seldom before c, g, qu."

L&S continue, saying that atque

indicat[es] a close internal connection between single words or whole clauses; while et designates an external connection of diff. objects with each other

So, it seems these would make sense:

mulier ac mater
(a woman and also a mother ← related)


pater et arbor
(a father and a tree ← unrelated)

Bennett also mentions that -que binds more tightly than atque.

It seems this analogy would hold:

vel : aut :: atque : et

"inclusive disjunction" : "exclusive disjunction" :: "inclusive conjunction" : "exclusive conjunction"

As I mention in my comment here, L&S §C of "sive/seu" says it's disjunctive.

(Interestingly, L&S also says vel was sometimes used in a "purely disjunctive sense," so there is some evolution in these "or" words.)


There is a long and very thorough explanation under ‘and’ in Smith & Hall’s Copious & Critical English-Latin Dictionary, which is readily available in various forms. (The authors also refer the reader to Allen’s Doctrina Cop. Ling. Latinae, which I have not been able to trace, but is probably 19th century and available in specialised academic libraries.)


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.