In linguistic prescriptivism, a solecism is a grammatical or other mistake or absurdity.
Some examples of usages often regarded as solecisms in standard English are:
-"This is just between you and I." for "This is just between you and me." (hypercorrection arising from attempts to avoid the common "you and me" form in the subject of sentences; "me" is in fact the correct pronoun for the object of a preposition.)
-"He ain't going." for "He's not going." (dialectic usage; see ain't)
Read more at Wikipedia