mean / mesne / mien are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
mean: (noun) an average of n numbers computed by adding some function of the numbers and dividing by some function of n. (verb) mean or intend to express or convey. (verb) denote or connote. (verb) have a specified degree of importance. (verb) destine or designate for a certain purpose. (adjective) excellent. (adjective) (used of persons or behavior) characterized by or indicative of lack of generosity.
mesne: NA
mien: NA
mean: m·IY·n
mesne: NA
mien: m·IY·n
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)